diff --git a/packages/docusaurus-mdx-loader/src/deps.d.ts b/packages/docusaurus-mdx-loader/src/deps.d.ts
index f4adca18b3c8..510bfc74e092 100644
--- a/packages/docusaurus-mdx-loader/src/deps.d.ts
+++ b/packages/docusaurus-mdx-loader/src/deps.d.ts
@@ -10,13 +10,13 @@ declare module '@mdx-js/mdx' {
   import type {Processor} from 'unified';
   import type {RemarkOrRehypePlugin} from '@docusaurus/mdx-loader';
 
-  export interface Options {
+  export type Options = {
     filepath?: string;
     skipExport?: boolean;
     wrapExport?: string;
     remarkPlugins?: RemarkOrRehypePlugin[];
     rehypePlugins?: RemarkOrRehypePlugin[];
-  }
+  };
 
   export function sync(content: string, options?: Options): string;
   export function createMdxAstCompiler(options?: Options): Processor;
diff --git a/packages/docusaurus-mdx-loader/src/index.ts b/packages/docusaurus-mdx-loader/src/index.ts
index 8d6e55c79c5e..4991f774cf1e 100644
--- a/packages/docusaurus-mdx-loader/src/index.ts
+++ b/packages/docusaurus-mdx-loader/src/index.ts
@@ -182,9 +182,9 @@ export default async function mdxLoader(
   // Partial are not expected to have associated metadata files or front matter
   const isMDXPartial = options.isMDXPartial?.(filePath);
   if (isMDXPartial && hasFrontMatter) {
-    const errorMessage = `Docusaurus MDX partial files should not contain FrontMatter.
+    const errorMessage = `Docusaurus MDX partial files should not contain front matter.
 Those partial files use the _ prefix as a convention by default, but this is configurable.
-File at ${filePath} contains FrontMatter that will be ignored:
+File at ${filePath} contains front matter that will be ignored:
 ${JSON.stringify(frontMatter, null, 2)}`;
 
     if (!options.isMDXPartialFrontMatterWarningDisabled) {
diff --git a/packages/docusaurus-mdx-loader/src/remark/headings/index.ts b/packages/docusaurus-mdx-loader/src/remark/headings/index.ts
index c964b8d266c1..51b0cb6c7bbd 100644
--- a/packages/docusaurus-mdx-loader/src/remark/headings/index.ts
+++ b/packages/docusaurus-mdx-loader/src/remark/headings/index.ts
@@ -9,9 +9,8 @@
 
 import {parseMarkdownHeadingId, createSlugger} from '@docusaurus/utils';
 import visit from 'unist-util-visit';
-import toString from 'mdast-util-to-string';
+import mdastToString from 'mdast-util-to-string';
 import type {Transformer} from 'unified';
-import type {Parent} from 'unist';
 import type {Heading, Text} from 'mdast';
 
 export default function plugin(): Transformer {
@@ -30,10 +29,8 @@ export default function plugin(): Transformer {
         const headingTextNodes = headingNode.children.filter(
           ({type}) => !['html', 'jsx'].includes(type),
         );
-        const heading = toString(
-          headingTextNodes.length > 0
-            ? ({children: headingTextNodes} as Parent)
-            : headingNode,
+        const heading = mdastToString(
+          headingTextNodes.length > 0 ? headingTextNodes : headingNode,
         );
 
         // Support explicit heading IDs
diff --git a/packages/docusaurus-mdx-loader/src/remark/toc/index.ts b/packages/docusaurus-mdx-loader/src/remark/toc/index.ts
index e733d5ab93a4..e10dbe70a3f3 100644
--- a/packages/docusaurus-mdx-loader/src/remark/toc/index.ts
+++ b/packages/docusaurus-mdx-loader/src/remark/toc/index.ts
@@ -27,9 +27,9 @@ const isImport = (child: Node): child is Literal => child.type === 'import';
 const hasImports = (index: number) => index > -1;
 const isExport = (child: Node): child is Literal => child.type === 'export';
 
-interface PluginOptions {
+type PluginOptions = {
   name?: string;
-}
+};
 
 const isTarget = (child: Literal, name: string) => {
   let found = false;
diff --git a/packages/docusaurus-migrate/src/types.ts b/packages/docusaurus-migrate/src/types.ts
index 8a3583fcfad2..022139f3489d 100644
--- a/packages/docusaurus-migrate/src/types.ts
+++ b/packages/docusaurus-migrate/src/types.ts
@@ -37,7 +37,7 @@ export type SidebarEntries = {
     | Array<{[key: string]: unknown} | string>;
 };
 
-export interface VersionTwoConfig {
+export type VersionTwoConfig = {
   baseUrl: string;
   favicon: string;
   tagline?: string;
@@ -93,7 +93,7 @@ export interface VersionTwoConfig {
         [key: string]: unknown;
       }
   )[];
-}
+};
 
 export type VersionOneConfig = {
   title?: string;
diff --git a/packages/docusaurus-module-type-aliases/src/index.d.ts b/packages/docusaurus-module-type-aliases/src/index.d.ts
index 0e4b69c68759..9d98309ef69c 100644
--- a/packages/docusaurus-module-type-aliases/src/index.d.ts
+++ b/packages/docusaurus-module-type-aliases/src/index.d.ts
@@ -140,8 +140,9 @@ declare module '@docusaurus/Head' {
 
 declare module '@docusaurus/Link' {
   import type {CSSProperties, ComponentProps} from 'react';
+  import type {NavLinkProps as RRNavLinkProps} from 'react-router-dom';
 
-  type NavLinkProps = Partial<import('react-router-dom').NavLinkProps>;
+  type NavLinkProps = Partial<RRNavLinkProps>;
   export type Props = NavLinkProps &
     ComponentProps<'a'> & {
       readonly className?: string;
diff --git a/packages/docusaurus-plugin-content-blog/src/__tests__/frontMatter.test.ts b/packages/docusaurus-plugin-content-blog/src/__tests__/frontMatter.test.ts
index 99e3c694bfbd..cb1020c680ef 100644
--- a/packages/docusaurus-plugin-content-blog/src/__tests__/frontMatter.test.ts
+++ b/packages/docusaurus-plugin-content-blog/src/__tests__/frontMatter.test.ts
@@ -314,7 +314,10 @@ describe('validateBlogPostFrontMatter tags', () => {
       {tags: ['hello', {label: 'tagLabel', permalink: '/tagPermalink'}]},
     ],
     invalidFrontMatters: [
-      [{tags: ''}, '"tags" does not look like a valid FrontMatter Yaml array.'],
+      [
+        {tags: ''},
+        '"tags" does not look like a valid front matter Yaml array.',
+      ],
       [{tags: ['']}, 'not allowed to be empty'],
     ],
     // See https://github.com/facebook/docusaurus/issues/4642
diff --git a/packages/docusaurus-plugin-content-blog/src/index.ts b/packages/docusaurus-plugin-content-blog/src/index.ts
index c1b8d82089ef..3414d2820a07 100644
--- a/packages/docusaurus-plugin-content-blog/src/index.ts
+++ b/packages/docusaurus-plugin-content-blog/src/index.ts
@@ -102,7 +102,7 @@ export default async function pluginContentBlog(
       ) as string[];
     },
 
-    async getTranslationFiles() {
+    getTranslationFiles() {
       return getTranslationFiles(options);
     },
 
diff --git a/packages/docusaurus-plugin-content-blog/src/plugin-content-blog.d.ts b/packages/docusaurus-plugin-content-blog/src/plugin-content-blog.d.ts
index e7fd5a65ab88..1733bff9bc16 100644
--- a/packages/docusaurus-plugin-content-blog/src/plugin-content-blog.d.ts
+++ b/packages/docusaurus-plugin-content-blog/src/plugin-content-blog.d.ts
@@ -10,7 +10,7 @@ declare module '@docusaurus/plugin-content-blog' {
   import type {FrontMatterTag, Tag} from '@docusaurus/utils';
   import type {Overwrite} from 'utility-types';
 
-  export interface Assets {
+  export type Assets = {
     /**
      * If `metadata.image` is a collocated image path, this entry will be the
      * bundler-generated image path. Otherwise, it's empty, and the image URL
@@ -25,13 +25,9 @@ declare module '@docusaurus/plugin-content-blog' {
      * should be accessed through `authors.imageURL`.
      */
     authorsImageUrls: (string | undefined)[];
-  }
+  };
 
-  /**
-   * Unknown keys are allowed, so that we can pass custom fields to authors,
-   * e.g., `twitter`.
-   */
-  export interface Author extends Record<string, unknown> {
+  export type Author = {
     /**
      * If `name` doesn't exist, an `imageURL` is expected.
      */
@@ -55,7 +51,12 @@ declare module '@docusaurus/plugin-content-blog' {
      * to generate a fallback `mailto:` URL.
      */
     email?: string;
-  }
+    /**
+     * Unknown keys are allowed, so that we can pass custom fields to authors,
+     * e.g., `twitter`.
+     */
+    [key: string]: unknown;
+  };
 
   /**
    * Everything is partial/unnormalized, because front matter is always
@@ -443,8 +444,6 @@ declare module '@theme/BlogPostPage' {
   >;
 
   export type Content = {
-    // TODO remove this. `metadata.frontMatter` is preferred because it can be
-    // accessed in enhanced plugins
     /** Same as `metadata.frontMatter` */
     readonly frontMatter: FrontMatter;
     /**
diff --git a/packages/docusaurus-plugin-content-blog/src/types.ts b/packages/docusaurus-plugin-content-blog/src/types.ts
index a96390f71d51..220ddbf1d579 100644
--- a/packages/docusaurus-plugin-content-blog/src/types.ts
+++ b/packages/docusaurus-plugin-content-blog/src/types.ts
@@ -11,39 +11,41 @@ import type {Metadata as BlogPaginatedMetadata} from '@theme/BlogListPage';
 
 export type BlogContentPaths = ContentPaths;
 
-export interface BlogContent {
+export type BlogContent = {
   blogSidebarTitle: string;
   blogPosts: BlogPost[];
   blogListPaginated: BlogPaginated[];
   blogTags: BlogTags;
   blogTagsListPath: string | null;
-}
+};
 
-export interface BlogTags {
+export type BlogTags = {
   // TODO, the key is the tag slug/permalink
   // This is due to legacy frontmatter: tags:
   // [{label: "xyz", permalink: "/1"}, {label: "xyz", permalink: "/2"}]
   // Soon we should forbid declaring permalink through frontmatter
   [tagKey: string]: BlogTag;
-}
+};
 
-export interface BlogTag {
+export type BlogTag = {
   name: string;
-  items: string[]; // blog post permalinks
+  /** Blog post permalinks. */
+  items: string[];
   permalink: string;
   pages: BlogPaginated[];
-}
+};
 
-export interface BlogPost {
+export type BlogPost = {
   id: string;
   metadata: BlogPostMetadata;
   content: string;
-}
+};
 
-export interface BlogPaginated {
+export type BlogPaginated = {
   metadata: BlogPaginatedMetadata;
-  items: string[]; // blog post permalinks
-}
+  /** Blog post permalinks. */
+  items: string[];
+};
 
 export type BlogBrokenMarkdownLink = BrokenMarkdownLink<BlogContentPaths>;
 export type BlogMarkdownLoaderOptions = {
diff --git a/packages/docusaurus-plugin-content-docs/src/__tests__/frontMatter.test.ts b/packages/docusaurus-plugin-content-docs/src/__tests__/frontMatter.test.ts
index 7e295afb0cb0..40f2f3f54fee 100644
--- a/packages/docusaurus-plugin-content-docs/src/__tests__/frontMatter.test.ts
+++ b/packages/docusaurus-plugin-content-docs/src/__tests__/frontMatter.test.ts
@@ -265,10 +265,13 @@ describe('validateDocFrontMatter tags', () => {
     validFrontMatters: [{}, {tags: undefined}, {tags: ['tag1', 'tag2']}],
     convertibleFrontMatter: [[{tags: ['tag1', 42]}, {tags: ['tag1', '42']}]],
     invalidFrontMatters: [
-      [{tags: 42}, '"tags" does not look like a valid FrontMatter Yaml array.'],
+      [
+        {tags: 42},
+        '"tags" does not look like a valid front matter Yaml array.',
+      ],
       [
         {tags: 'tag1, tag2'},
-        '"tags" does not look like a valid FrontMatter Yaml array.',
+        '"tags" does not look like a valid front matter Yaml array.',
       ],
       [{tags: [{}]}, '"tags[0]" does not look like a valid tag'],
       [{tags: [true]}, '"tags[0]" does not look like a valid tag'],
diff --git a/packages/docusaurus-plugin-content-docs/src/index.ts b/packages/docusaurus-plugin-content-docs/src/index.ts
index ed35fa390c55..a0dc21768960 100644
--- a/packages/docusaurus-plugin-content-docs/src/index.ts
+++ b/packages/docusaurus-plugin-content-docs/src/index.ts
@@ -106,7 +106,7 @@ export default async function pluginContentDocs(
         });
     },
 
-    async getTranslationFiles({content}) {
+    getTranslationFiles({content}) {
       return getLoadedContentTranslationFiles(content);
     },
 
diff --git a/packages/docusaurus-plugin-content-docs/src/plugin-content-docs.d.ts b/packages/docusaurus-plugin-content-docs/src/plugin-content-docs.d.ts
index 92d375fc700a..271bfa4923db 100644
--- a/packages/docusaurus-plugin-content-docs/src/plugin-content-docs.d.ts
+++ b/packages/docusaurus-plugin-content-docs/src/plugin-content-docs.d.ts
@@ -10,9 +10,9 @@ declare module '@docusaurus/plugin-content-docs' {
   import type {ContentPaths, Tag, FrontMatterTag} from '@docusaurus/utils';
   import type {Required} from 'utility-types';
 
-  export interface Assets {
+  export type Assets = {
     image?: string;
-  }
+  };
 
   /**
    * Custom callback for parsing number prefixes from file/folder names.
diff --git a/packages/docusaurus-plugin-content-docs/src/sidebars/types.ts b/packages/docusaurus-plugin-content-docs/src/sidebars/types.ts
index 9f4d68a3ae45..2dfaf5b7f553 100644
--- a/packages/docusaurus-plugin-content-docs/src/sidebars/types.ts
+++ b/packages/docusaurus-plugin-content-docs/src/sidebars/types.ts
@@ -254,18 +254,15 @@ export type SidebarItemsGenerator = (
   generatorArgs: SidebarItemsGeneratorArgs,
 ) => Promise<NormalizedSidebar>;
 
-// Also inject the default generator to conveniently wrap/enhance/sort the
-// default sidebar gen logic
-// see https://github.com/facebook/docusaurus/issues/4640#issuecomment-822292320
-export type SidebarItemsGeneratorOptionArgs = {
-  /**
-   * Useful to re-use/enhance the default sidebar generation logic from
-   * Docusaurus.
-   */
-  defaultSidebarItemsGenerator: SidebarItemsGenerator;
-} & SidebarItemsGeneratorArgs;
 export type SidebarItemsGeneratorOption = (
-  generatorArgs: SidebarItemsGeneratorOptionArgs,
+  generatorArgs: {
+    /**
+     * Useful to re-use/enhance the default sidebar generation logic from
+     * Docusaurus.
+     * @see https://github.com/facebook/docusaurus/issues/4640#issuecomment-822292320
+     */
+    defaultSidebarItemsGenerator: SidebarItemsGenerator;
+  } & SidebarItemsGeneratorArgs,
 ) => Promise<NormalizedSidebarItem[]>;
 
 export type SidebarProcessorParams = {
diff --git a/packages/docusaurus-plugin-ideal-image/src/deps.d.ts b/packages/docusaurus-plugin-ideal-image/src/deps.d.ts
index 769d0561cc60..839a35fac984 100644
--- a/packages/docusaurus-plugin-ideal-image/src/deps.d.ts
+++ b/packages/docusaurus-plugin-ideal-image/src/deps.d.ts
@@ -33,12 +33,12 @@ declare module '@endiliey/react-ideal-image' {
     | 'noicon'
     | 'offline';
 
-  export interface SrcType {
+  export type SrcType = {
     width: number;
     src?: string;
     size?: number;
     format?: 'webp' | 'jpeg' | 'png' | 'gif';
-  }
+  };
 
   type ThemeKey = 'placeholder' | 'img' | 'icon' | 'noscript';
 
diff --git a/packages/docusaurus-remark-plugin-npm2yarn/src/index.ts b/packages/docusaurus-remark-plugin-npm2yarn/src/index.ts
index 19c03c4b21c5..0764763e9540 100644
--- a/packages/docusaurus-remark-plugin-npm2yarn/src/index.ts
+++ b/packages/docusaurus-remark-plugin-npm2yarn/src/index.ts
@@ -11,9 +11,9 @@ import type {Node, Parent} from 'unist';
 import visit from 'unist-util-visit';
 import npmToYarn from 'npm-to-yarn';
 
-interface PluginOptions {
+type PluginOptions = {
   sync?: boolean;
-}
+};
 
 // E.g. global install: 'npm i' -> 'yarn'
 const convertNpmToYarn = (npmCode: string) => npmToYarn(npmCode, 'yarn');
diff --git a/packages/docusaurus-theme-classic/src/index.ts b/packages/docusaurus-theme-classic/src/index.ts
index 64f56392a45e..8aa1c7b805ad 100644
--- a/packages/docusaurus-theme-classic/src/index.ts
+++ b/packages/docusaurus-theme-classic/src/index.ts
@@ -118,7 +118,7 @@ export default function docusaurusThemeClassic(
       return '../src/theme';
     },
 
-    getTranslationFiles: async () => getTranslationFiles({themeConfig}),
+    getTranslationFiles: () => getTranslationFiles({themeConfig}),
 
     translateThemeConfig: (params) =>
       translateThemeConfig({
diff --git a/packages/docusaurus-theme-common/src/contexts/docsSidebar.tsx b/packages/docusaurus-theme-common/src/contexts/docsSidebar.tsx
index 2fb4d1cb0f19..56aacc9380ed 100644
--- a/packages/docusaurus-theme-common/src/contexts/docsSidebar.tsx
+++ b/packages/docusaurus-theme-common/src/contexts/docsSidebar.tsx
@@ -13,11 +13,11 @@ import {ReactContextError} from '../utils/reactUtils';
 // Inspired by https://github.com/jamiebuilds/unstated-next/blob/master/src/unstated-next.tsx
 const EmptyContext: unique symbol = Symbol('EmptyContext');
 
-type SidebarContextValue = {name: string; items: PropSidebar};
+type ContextValue = {name: string; items: PropSidebar};
 
-const Context = React.createContext<
-  SidebarContextValue | null | typeof EmptyContext
->(EmptyContext);
+const Context = React.createContext<ContextValue | null | typeof EmptyContext>(
+  EmptyContext,
+);
 
 /**
  * Provide the current sidebar to your children.
@@ -31,7 +31,7 @@ export function DocsSidebarProvider({
   name: string | undefined;
   items: PropSidebar | undefined;
 }): JSX.Element {
-  const stableValue: SidebarContextValue | null = useMemo(
+  const stableValue: ContextValue | null = useMemo(
     () =>
       name && items
         ? {
@@ -45,9 +45,9 @@ export function DocsSidebarProvider({
 }
 
 /**
- * Gets the sidebar data that's currently displayed, or `null` if there isn't one
+ * Gets the sidebar that's currently displayed, or `null` if there isn't one
  */
-export function useDocsSidebar(): SidebarContextValue | null {
+export function useDocsSidebar(): ContextValue | null {
   const value = useContext(Context);
   if (value === EmptyContext) {
     throw new ReactContextError('DocsSidebarProvider');
diff --git a/packages/docusaurus-theme-common/src/utils/docsUtils.tsx b/packages/docusaurus-theme-common/src/utils/docsUtils.tsx
index 64e700a48722..13e63bd44def 100644
--- a/packages/docusaurus-theme-common/src/utils/docsUtils.tsx
+++ b/packages/docusaurus-theme-common/src/utils/docsUtils.tsx
@@ -220,8 +220,9 @@ export function useDocsVersionCandidates(
 
 /**
  * The layout components, like navbar items, must be able to work on all pages,
- * even on non-doc ones. This hook would always return a sidebar to be linked
- * to. See also {@link useDocsVersionCandidates} for how this selection is done.
+ * even on non-doc ones where there's no version context, so a sidebar ID could
+ * be ambiguous. This hook would always return a sidebar to be linked to. See
+ * also {@link useDocsVersionCandidates} for how this selection is done.
  *
  * @throws This hook throws if a sidebar with said ID is not found.
  */
@@ -252,8 +253,9 @@ export function useLayoutDocsSidebar(
 
 /**
  * The layout components, like navbar items, must be able to work on all pages,
- * even on non-doc ones. This hook would always return a doc to be linked
- * to. See also {@link useDocsVersionCandidates} for how this selection is done.
+ * even on non-doc ones where there's no version context, so a doc ID could be
+ * ambiguous. This hook would always return a doc to be linked to. See also
+ * {@link useDocsVersionCandidates} for how this selection is done.
  *
  * @throws This hook throws if a doc with said ID is not found.
  */
diff --git a/packages/docusaurus-theme-common/src/utils/metadataUtils.tsx b/packages/docusaurus-theme-common/src/utils/metadataUtils.tsx
index d7b85f0d04b3..9610faa2e40b 100644
--- a/packages/docusaurus-theme-common/src/utils/metadataUtils.tsx
+++ b/packages/docusaurus-theme-common/src/utils/metadataUtils.tsx
@@ -12,13 +12,13 @@ import useRouteContext from '@docusaurus/useRouteContext';
 import {useBaseUrlUtils} from '@docusaurus/useBaseUrl';
 import {useTitleFormatter} from './generalUtils';
 
-interface PageMetadataProps {
+type PageMetadataProps = {
   readonly title?: string;
   readonly description?: string;
   readonly keywords?: readonly string[] | string;
   readonly image?: string;
   readonly children?: ReactNode;
-}
+};
 
 /**
  * Helper component to manipulate page metadata and override site defaults.
diff --git a/packages/docusaurus-theme-common/src/utils/storageUtils.ts b/packages/docusaurus-theme-common/src/utils/storageUtils.ts
index d5dcbdc8c3f5..08ab3be1aee8 100644
--- a/packages/docusaurus-theme-common/src/utils/storageUtils.ts
+++ b/packages/docusaurus-theme-common/src/utils/storageUtils.ts
@@ -54,11 +54,11 @@ Possible reasons: running Docusaurus in an iframe, in an incognito browser sessi
 }
 
 // Convenient storage interface for a single storage key
-export interface StorageSlot {
+export type StorageSlot = {
   get: () => string | null;
   set: (value: string) => void;
   del: () => void;
-}
+};
 
 const NoopStorageSlot: StorageSlot = {
   get: () => null,
diff --git a/packages/docusaurus-theme-common/src/utils/tocUtils.ts b/packages/docusaurus-theme-common/src/utils/tocUtils.ts
index c5a7fc9c6659..2b83f1a2f920 100644
--- a/packages/docusaurus-theme-common/src/utils/tocUtils.ts
+++ b/packages/docusaurus-theme-common/src/utils/tocUtils.ts
@@ -101,7 +101,7 @@ function filterTOC({
  * to ensure that weird TOC structures preserve their semantics. For example, an
  * h3-h2-h4 sequence should not be treeified as an "h3 > h4" hierarchy with
  * min=3, max=4, but should rather be "[h3, h4]" (since the h2 heading has split
- * the two headings and they are not parents)
+ * the two headings and they are not parent-children)
  */
 export function useFilteredAndTreeifiedTOC({
   toc,
diff --git a/packages/docusaurus-theme-live-codeblock/src/deps.d.ts b/packages/docusaurus-theme-live-codeblock/src/deps.d.ts
index 57918444adca..036cdb62f1b6 100644
--- a/packages/docusaurus-theme-live-codeblock/src/deps.d.ts
+++ b/packages/docusaurus-theme-live-codeblock/src/deps.d.ts
@@ -10,10 +10,10 @@ declare module '@philpl/buble' {
   // eslint-disable-next-line import/no-extraneous-dependencies, no-restricted-syntax
   export * from 'buble';
   export const features: string[];
-  export interface TransformOptions extends OriginalTransformOptions {
+  export type TransformOptions = OriginalTransformOptions & {
     transforms?: OriginalTransformOptions['transforms'] & {
       asyncAwait?: boolean;
       getterSetter?: boolean;
     };
-  }
+  };
 }
diff --git a/packages/docusaurus-theme-live-codeblock/src/theme-live-codeblock.d.ts b/packages/docusaurus-theme-live-codeblock/src/theme-live-codeblock.d.ts
index b377abadb66a..5bb5e51d2d26 100644
--- a/packages/docusaurus-theme-live-codeblock/src/theme-live-codeblock.d.ts
+++ b/packages/docusaurus-theme-live-codeblock/src/theme-live-codeblock.d.ts
@@ -23,9 +23,9 @@ declare module '@theme/Playground' {
 }
 
 declare module '@theme/ReactLiveScope' {
-  interface Scope {
+  type Scope = {
     [key: string]: unknown;
-  }
+  };
 
   const ReactLiveScope: Scope;
   export default ReactLiveScope;
diff --git a/packages/docusaurus-types/src/index.d.ts b/packages/docusaurus-types/src/index.d.ts
index 58969aa81136..7bc1f119a2ee 100644
--- a/packages/docusaurus-types/src/index.d.ts
+++ b/packages/docusaurus-types/src/index.d.ts
@@ -86,7 +86,7 @@ export type DocusaurusConfig = {
     | string
     | {
         src: string;
-        [key: string]: unknown;
+        [key: string]: string | boolean | undefined;
       }
   )[];
   clientModules: string[];
@@ -96,7 +96,7 @@ export type DocusaurusConfig = {
     | string
     | {
         href: string;
-        [key: string]: unknown;
+        [key: string]: string | boolean | undefined;
       }
   )[];
   titleDelimiter?: string;
@@ -304,16 +304,16 @@ export type ThemeConfigValidationContext<T> = {
 
 export type Plugin<Content = unknown> = {
   name: string;
-  loadContent?: () => Promise<Content>;
+  loadContent?: () => Promise<Content> | Content;
   contentLoaded?: (args: {
     /** the content loaded by this plugin instance */
     content: Content; //
     /** content loaded by ALL the plugins */
     allContent: AllContent;
     actions: PluginContentLoadedActions;
-  }) => Promise<void>;
+  }) => Promise<void> | void;
   routesLoaded?: (routes: RouteConfig[]) => void; // TODO remove soon, deprecated (alpha-60)
-  postBuild?: (props: Props & {content: Content}) => Promise<void>;
+  postBuild?: (props: Props & {content: Content}) => Promise<void> | void;
   // TODO refactor the configureWebpack API surface: use an object instead of
   // multiple params (requires breaking change)
   configureWebpack?: (
@@ -342,8 +342,10 @@ export type Plugin<Content = unknown> = {
   // translations
   getTranslationFiles?: (args: {
     content: Content;
-  }) => Promise<TranslationFile[]>;
-  getDefaultCodeTranslationMessages?: () => Promise<{[id: string]: string}>;
+  }) => Promise<TranslationFile[]> | TranslationFile[];
+  getDefaultCodeTranslationMessages?: () =>
+    | Promise<{[id: string]: string}>
+    | {[id: string]: string};
   translateContent?: (args: {
     /** The content loaded by this plugin instance. */
     content: Content;
diff --git a/packages/docusaurus-utils-validation/src/validationSchemas.ts b/packages/docusaurus-utils-validation/src/validationSchemas.ts
index f49b962a853b..4e6134a7b2a1 100644
--- a/packages/docusaurus-utils-validation/src/validationSchemas.ts
+++ b/packages/docusaurus-utils-validation/src/validationSchemas.ts
@@ -83,7 +83,7 @@ export const FrontMatterTagsSchema = JoiFrontMatter.array()
   .items(FrontMatterTagSchema)
   .messages({
     'array.base':
-      '{{#label}} does not look like a valid FrontMatter Yaml array.',
+      '{{#label}} does not look like a valid front matter Yaml array.',
   });
 
 export const FrontMatterTOCHeadingLevels = {
diff --git a/packages/docusaurus/src/client/PendingNavigation.tsx b/packages/docusaurus/src/client/PendingNavigation.tsx
index 56e7e9c062b5..d9a87706a1fa 100644
--- a/packages/docusaurus/src/client/PendingNavigation.tsx
+++ b/packages/docusaurus/src/client/PendingNavigation.tsx
@@ -19,18 +19,18 @@ import './nprogress.css';
 
 nprogress.configure({showSpinner: false});
 
-interface Props extends RouteComponentProps {
+type Props = RouteComponentProps & {
   readonly routes: RouteConfig[];
   readonly delay: number;
   readonly location: Location;
-}
-interface State {
+};
+type State = {
   nextRouteHasLoaded: boolean;
-}
+};
 
 class PendingNavigation extends React.Component<Props, State> {
-  previousLocation: Location | null;
-  progressBarTimeout: NodeJS.Timeout | null;
+  private previousLocation: Location | null;
+  private progressBarTimeout: NodeJS.Timeout | null;
 
   constructor(props: Props) {
     super(props);
diff --git a/packages/docusaurus/src/client/exports/ErrorBoundary.tsx b/packages/docusaurus/src/client/exports/ErrorBoundary.tsx
index 9b9515898a84..5fc50be15dbd 100644
--- a/packages/docusaurus/src/client/exports/ErrorBoundary.tsx
+++ b/packages/docusaurus/src/client/exports/ErrorBoundary.tsx
@@ -11,9 +11,9 @@ import ExecutionEnvironment from '@docusaurus/ExecutionEnvironment';
 import type {Props} from '@docusaurus/ErrorBoundary';
 import DefaultFallback from '@theme/Error';
 
-interface State {
+type State = {
   error: Error | null;
-}
+};
 
 export default class ErrorBoundary extends React.Component<Props, State> {
   constructor(props: Props) {
diff --git a/packages/docusaurus/src/deps.d.ts b/packages/docusaurus/src/deps.d.ts
index f977549c7c7a..acaccfcebb0c 100644
--- a/packages/docusaurus/src/deps.d.ts
+++ b/packages/docusaurus/src/deps.d.ts
@@ -26,9 +26,9 @@ declare module 'react-loadable-ssr-addon-v5-slorber' {
     modulesToBeLoaded: string[],
   ): {js: Asset[]; css: Asset[]};
 
-  interface ReactLoadableSSRAddon {
+  type ReactLoadableSSRAddon = {
     new (props: {filename: string});
-  }
+  };
 
   const plugin: ReactLoadableSSRAddon;
   export default plugin;
@@ -47,7 +47,7 @@ declare module '@slorber/static-site-generator-webpack-plugin' {
     noIndex: boolean;
   };
 
-  interface StaticSiteGeneratorPlugin {
+  type StaticSiteGeneratorPlugin = {
     new (props: {
       entry: string;
       locals: Locals;
@@ -55,7 +55,7 @@ declare module '@slorber/static-site-generator-webpack-plugin' {
       preferFoldersOutput?: boolean;
       globals: {[key: string]: unknown};
     });
-  }
+  };
 
   const plugin: StaticSiteGeneratorPlugin;
   export default plugin;
diff --git a/packages/docusaurus/src/server/plugins/synthetic.ts b/packages/docusaurus/src/server/plugins/synthetic.ts
index f44fad1eb3d8..67e297ffe5f5 100644
--- a/packages/docusaurus/src/server/plugins/synthetic.ts
+++ b/packages/docusaurus/src/server/plugins/synthetic.ts
@@ -36,26 +36,27 @@ export function createBootstrapPlugin({
       return siteConfigClientModules;
     },
     injectHtmlTags: () => {
-      const stylesheetsTags = stylesheets.map((source) =>
-        typeof source === 'string'
-          ? `<link rel="stylesheet" href="${source}">`
-          : ({
-              tagName: 'link',
-              attributes: {
-                rel: 'stylesheet',
-                ...source,
+      const stylesheetsTags = stylesheets.map(
+        (source): string | HtmlTagObject =>
+          typeof source === 'string'
+            ? `<link rel="stylesheet" href="${source}">`
+            : {
+                tagName: 'link',
+                attributes: {
+                  rel: 'stylesheet',
+                  ...source,
+                },
               },
-            } as HtmlTagObject),
       );
-      const scriptsTags = scripts.map((source) =>
+      const scriptsTags = scripts.map((source): string | HtmlTagObject =>
         typeof source === 'string'
           ? `<script src="${source}"></script>`
-          : ({
+          : {
               tagName: 'script',
               attributes: {
                 ...source,
               },
-            } as HtmlTagObject),
+            },
       );
       return {
         headTags: [...stylesheetsTags, ...scriptsTags],
diff --git a/packages/docusaurus/src/webpack/plugins/CleanWebpackPlugin.ts b/packages/docusaurus/src/webpack/plugins/CleanWebpackPlugin.ts
index e6bae7173dea..46b4ca424fde 100644
--- a/packages/docusaurus/src/webpack/plugins/CleanWebpackPlugin.ts
+++ b/packages/docusaurus/src/webpack/plugins/CleanWebpackPlugin.ts
@@ -33,7 +33,7 @@ import type {Compiler, Stats} from 'webpack';
 import path from 'path';
 import {sync as delSync} from 'del';
 
-export interface Options {
+export type Options = {
   /**
    * Write Logs to Console
    * (Always enabled when dry is true)
@@ -65,7 +65,7 @@ export interface Options {
    * default: ['**\/*']
    */
   cleanOnceBeforeBuildPatterns?: string[];
-}
+};
 
 export default class CleanWebpackPlugin {
   private readonly verbose: boolean;
diff --git a/packages/docusaurus/src/webpack/plugins/WaitPlugin.ts b/packages/docusaurus/src/webpack/plugins/WaitPlugin.ts
index ab2130911647..2ace27913e4c 100644
--- a/packages/docusaurus/src/webpack/plugins/WaitPlugin.ts
+++ b/packages/docusaurus/src/webpack/plugins/WaitPlugin.ts
@@ -10,9 +10,9 @@ import fs from 'fs-extra';
 import waitOn from 'wait-on';
 import type {Compiler} from 'webpack';
 
-interface WaitPluginOptions {
+type WaitPluginOptions = {
   filepath: string;
-}
+};
 
 export default class WaitPlugin {
   filepath: string;
diff --git a/website/docs/api/plugin-methods/README.md b/website/docs/api/plugin-methods/README.md
index 0e9d816c6f6d..a59fc2059f47 100644
--- a/website/docs/api/plugin-methods/README.md
+++ b/website/docs/api/plugin-methods/README.md
@@ -24,13 +24,13 @@ The plugin module's default export is a constructor function with the signature
 `context` is plugin-agnostic, and the same object will be passed into all plugins used for a Docusaurus website. The `context` object contains the following fields:
 
 ```ts
-interface LoadContext {
+type LoadContext = {
   siteDir: string;
   generatedFilesDir: string;
   siteConfig: DocusaurusConfig;
   outDir: string;
   baseUrl: string;
-}
+};
 ```
 
 ### `options` {#options}
diff --git a/website/docs/api/plugin-methods/lifecycle-apis.md b/website/docs/api/plugin-methods/lifecycle-apis.md
index e963f401251e..bc583e8d38e0 100644
--- a/website/docs/api/plugin-methods/lifecycle-apis.md
+++ b/website/docs/api/plugin-methods/lifecycle-apis.md
@@ -43,17 +43,17 @@ The data that was loaded in `loadContent` will be consumed in `contentLoaded`. I
 Create a route to add to the website.
 
 ```ts
-interface RouteConfig {
+type RouteConfig = {
   path: string;
   component: string;
   modules?: RouteModules;
   routes?: RouteConfig[];
   exact?: boolean;
   priority?: number;
-}
-interface RouteModules {
+};
+type RouteModules = {
   [module: string]: Module | RouteModules | RouteModules[];
-}
+};
 type Module =
   | {
       path: string;
@@ -339,7 +339,7 @@ function injectHtmlTags(): {
 
 type HtmlTags = string | HtmlTagObject | (string | HtmlTagObject)[];
 
-interface HtmlTagObject {
+type HtmlTagObject = {
   /**
    * Attributes of the HTML tag
    * E.g. `{'disabled': true, 'value': 'demo', 'rel': 'preconnect'}`
@@ -355,7 +355,7 @@ interface HtmlTagObject {
    * The inner HTML
    */
   innerHTML?: string;
-}
+};
 ```
 
 Example:
diff --git a/website/docs/docusaurus-core.md b/website/docs/docusaurus-core.md
index fcd35040dd0d..26316d033364 100644
--- a/website/docs/docusaurus-core.md
+++ b/website/docs/docusaurus-core.md
@@ -341,31 +341,31 @@ type PluginVersionInformation =
   | {readonly type: 'local'}
   | {readonly type: 'synthetic'};
 
-interface SiteMetadata {
+type SiteMetadata = {
   readonly docusaurusVersion: string;
   readonly siteVersion?: string;
   readonly pluginVersions: Record<string, PluginVersionInformation>;
-}
+};
 
-interface I18nLocaleConfig {
+type I18nLocaleConfig = {
   label: string;
   direction: string;
-}
+};
 
-interface I18n {
+type I18n = {
   defaultLocale: string;
   locales: [string, ...string[]];
   currentLocale: string;
   localeConfigs: Record<string, I18nLocaleConfig>;
-}
+};
 
-interface DocusaurusContext {
+type DocusaurusContext = {
   siteConfig: DocusaurusConfig;
   siteMetadata: SiteMetadata;
   globalData: Record<string, unknown>;
   i18n: I18n;
   codeTranslations: Record<string, string>;
-}
+};
 ```
 
 Usage example:
diff --git a/website/src/components/Svg/index.tsx b/website/src/components/Svg/index.tsx
index 3fe951af3571..a37a4eddd7ed 100644
--- a/website/src/components/Svg/index.tsx
+++ b/website/src/components/Svg/index.tsx
@@ -9,14 +9,14 @@ import React, {type ReactNode, type ComponentProps} from 'react';
 import clsx from 'clsx';
 import styles from './styles.module.css';
 
-export interface SvgIconProps extends ComponentProps<'svg'> {
+export type SvgIconProps = ComponentProps<'svg'> & {
   viewBox?: string;
   size?: 'inherit' | 'small' | 'medium' | 'large';
   color?: 'inherit' | 'primary' | 'secondary' | 'success' | 'error' | 'warning';
   svgClass?: string; // Class attribute on the child
   colorAttr?: string; // Applies a color attribute to the SVG element.
   children: ReactNode; // Node passed into the SVG element.
-}
+};
 
 export default function Svg(props: SvgIconProps): JSX.Element {
   const {
diff --git a/website/src/components/TeamProfileCards/index.tsx b/website/src/components/TeamProfileCards/index.tsx
index 7c212fe38b39..92b6858df745 100644
--- a/website/src/components/TeamProfileCards/index.tsx
+++ b/website/src/components/TeamProfileCards/index.tsx
@@ -19,13 +19,13 @@ function WebsiteLink({to, children}: {to: string; children?: ReactNode}) {
   );
 }
 
-interface ProfileProps {
+type ProfileProps = {
   className?: string;
   name: string;
   children: ReactNode;
   githubUrl?: string;
   twitterUrl?: string;
-}
+};
 
 function TeamProfileCard({
   className,
diff --git a/website/src/data/tweets.tsx b/website/src/data/tweets.tsx
index 9656e1a5747b..157bc0fb0e67 100644
--- a/website/src/data/tweets.tsx
+++ b/website/src/data/tweets.tsx
@@ -9,9 +9,9 @@ import React from 'react';
 
 import type {Props as Tweet} from '../components/Tweet';
 
-export interface TweetItem extends Tweet {
+export type TweetItem = Tweet & {
   showOnHomepage: boolean;
-}
+};
 
 const TWEETS: TweetItem[] = [
   {