diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index c1f42b82..7f217c1b 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -54,14 +54,20 @@ properties:
 
 - `url`: same as the [`url`](README.md#url) property in `index.json`.
 - `shortname`: same as the [`shortname`](README.md#shortname) property in
-`index.json`.
+`index.json`. When the `forkOf` property is also set, note that the actual
+shortname in the final list will be prefixed by the shortname of the base
+spec (as in: `${forkOf}-fork-${shortname}`).
+- `forkOf`: same as the [`forkOf`](README.md#forkof) property in `index.json`.
+No need to set `seriesComposition` to `"fork"` when this property is set, the
+build logic will take care of that automatically.
 - `series`: same as the [`series`](README.md#series) property in `index.json`,
 but note the `currentSpecification` property will be ignored.
 - `seriesVersion`: same as the [`seriesVersion`](README.md#seriesversion)
 property in `index.json`.
 - `seriesComposition`: same as the [`seriesComposition`](README.md#seriesComposition)
-property in `index.json`. The property must only be set for delta spec (since
-full is the default).
+property in `index.json`. The property must only be set for delta spec, since
+full is the default and fork specs are identified through the `forkOf` property
+in `specs.json`.
 - `organization`: same as the [`organization`](README.md#organization) property
 in `index.json` to specify the name of the organization that owns the spec.
 - `groups`: same as the [`groups`](README.md#groups) property in `index.json`
diff --git a/README.md b/README.md
index ce6d5026..6eea8588 100644
--- a/README.md
+++ b/README.md
@@ -30,6 +30,8 @@ cross-references, WebIDL, quality, etc.
   - [`seriesComposition`](#seriescomposition)
   - [`seriesPrevious`](#seriesprevious)
   - [`seriesNext`](#seriesnext)
+  - [`forkOf`](#forkof)
+  - [`forks`](#forks)
   - [`organization`](#organization)
   - [`groups`](#groups)
   - [`release`](#release)
@@ -150,6 +152,13 @@ For WHATWG specs, this is the shortname that appears at the beginning of the URL
 (e.g. `compat` for `https://compat.spec.whatwg.org/`). For specs developed on
 GitHub, this is usually the name of repository that holds the spec.
 
+When the spec is a fork (see [`forkOf`](#forkof)) of a base spec, its shortname
+will start with the shortname of the base spec completed by `-fork-` and the
+actual shortname of the fork spec. For instance, given an exception handling
+fork of the WebAssembly spec for which the raw shortname would be
+`exception-handling`, the actual spec shortname will be
+`wasm-js-api-1-fork-exception-handling`.
+
 The `shortname` property is always set.
 
 
@@ -285,8 +294,9 @@ number.
 
 ### `seriesComposition`
 
-Whether the spec is a standalone spec, or whether it is a delta spec over the
-previous level or version in the series. Possible values are `full` or `delta`.
+Whether the spec is a standalone spec, whether it is a delta spec over the
+previous level or version in the series, or whether it is a temporary fork of
+another spec. Possible values are `full`, `delta`, or `fork`.
 
 The `seriesComposition` property is always set.
 
@@ -306,6 +316,28 @@ The `shortname` of the next spec in the series.
 The `seriesNext` property is only set where there is a next level or version.
 
 
+### `forkOf`
+
+The shortname of the spec that this spec is a fork of.
+
+The `forkOf` property is only set when the spec is a fork of another one. The
+[`seriesComposition`](#seriescomposition) property is always `"fork"` when the
+`forkOf` property is set.
+
+A forked specs is supposed to be temporary by nature. It will be removed from
+the list as soon as it gets merged into the main spec, or as soon as it gets
+abandoned.
+
+
+### `forks`
+
+An array that lists shortnames of known forks of the spec in the list.
+
+The `forks` property is only set when there exists at least one fork of the
+spec in the list, meaning when there is an entry in the list that has a
+[`forkOf`](#forkof) property set to the spec's shortname.
+
+
 ### `organization`
 
 The name of the standardization organization that owns the spec such as `W3C`,
diff --git a/packages/browser-specs/package.json b/packages/browser-specs/package.json
index 71801dc9..1e871c70 100644
--- a/packages/browser-specs/package.json
+++ b/packages/browser-specs/package.json
@@ -1,6 +1,6 @@
 {
   "name": "browser-specs",
-  "version": "2.30.1",
+  "version": "3.0.0",
   "description": "Curated list of technical Web specifications that are directly implemented or that will be implemented by Web browsers.",
   "repository": {
     "type": "git",
@@ -14,4 +14,4 @@
     "index.json"
   ],
   "main": "index.json"
-}
\ No newline at end of file
+}
diff --git a/packages/web-specs/package.json b/packages/web-specs/package.json
index 44334499..9cb8293e 100644
--- a/packages/web-specs/package.json
+++ b/packages/web-specs/package.json
@@ -1,6 +1,6 @@
 {
   "name": "web-specs",
-  "version": "1.3.1",
+  "version": "2.0.0",
   "description": "Curated list of technical Web specifications",
   "repository": {
     "type": "git",
@@ -14,4 +14,4 @@
     "index.json"
   ],
   "main": "index.json"
-}
\ No newline at end of file
+}
diff --git a/schema/definitions.json b/schema/definitions.json
index a17cce7d..0db66a50 100644
--- a/schema/definitions.json
+++ b/schema/definitions.json
@@ -47,7 +47,7 @@
 
     "seriesComposition": {
       "type": "string",
-      "enum": ["full", "delta"]
+      "enum": ["full", "delta", "fork"]
     },
 
     "forceCurrent": {
@@ -151,6 +151,11 @@
           "minItems": 1
         }
       ]
+    },
+
+    "forks": {
+      "type": "array",
+      "items": { "$ref": "#/$defs/shortname" }
     }
   }
 }
\ No newline at end of file
diff --git a/schema/index.json b/schema/index.json
index e7d42c3e..1c9d598a 100644
--- a/schema/index.json
+++ b/schema/index.json
@@ -8,6 +8,8 @@
     "properties": {
       "url": { "$ref": "definitions.json#/$defs/url" },
       "shortname": { "$ref": "definitions.json#/$defs/shortname" },
+      "forkOf": { "$ref": "definitions.json#/$defs/shortname" },
+      "forks": { "$ref": "definitions.json#/$defs/forks" },
       "series": { "$ref": "definitions.json#/$defs/series" },
       "seriesVersion": { "$ref": "definitions.json#/$defs/seriesVersion" },
       "seriesComposition": { "$ref": "definitions.json#/$defs/seriesComposition" },
diff --git a/schema/specs.json b/schema/specs.json
index 5fef7a5b..136da35d 100644
--- a/schema/specs.json
+++ b/schema/specs.json
@@ -14,6 +14,7 @@
         "properties": {
           "url": { "$ref": "definitions.json#/$defs/url" },
           "shortname": { "$ref": "definitions.json#/$defs/shortname" },
+          "forkOf": { "$ref": "definitions.json#/$defs/shortname" },
           "series": { "$ref": "definitions.json#/$defs/series" },
           "seriesVersion": { "$ref": "definitions.json#/$defs/seriesVersion" },
           "seriesComposition": { "$ref": "definitions.json#/$defs/seriesComposition" },
diff --git a/specs.json b/specs.json
index e3131350..a87104ce 100644
--- a/specs.json
+++ b/specs.json
@@ -181,6 +181,10 @@
   "https://w3c.github.io/webappsec-trusted-types/dist/spec/",
   "https://w3c.github.io/webdriver-bidi/",
   "https://w3c.github.io/webrtc-ice/",
+  {
+    "url": "https://webassembly.github.io/exception-handling/js-api/",
+    "forkOf": "wasm-js-api-1"
+  },
   "https://webbluetoothcg.github.io/web-bluetooth/",
   "https://webidl.spec.whatwg.org/",
   "https://websockets.spec.whatwg.org/",
diff --git a/src/build-index.js b/src/build-index.js
index 2fb209bc..a9156670 100644
--- a/src/build-index.js
+++ b/src/build-index.js
@@ -93,9 +93,11 @@ async function generateIndex(specs, { previousIndex = null, log = console.log }
       delete spec.series;
 
       // Complete information
+      const seriesComposition = spec.seriesComposition ??
+        (spec.forkOf ? "fork" : "full");
       const res = Object.assign(
-        { url: spec.url, seriesComposition: spec.seriesComposition || "full" },
-        computeShortname(spec.shortname || spec.url),
+        { url: spec.url, seriesComposition },
+        computeShortname(spec.shortname ?? spec.url, spec.forkOf),
         spec);
 
       // Restore series info explicitly set in initial spec object
@@ -114,7 +116,20 @@ async function generateIndex(specs, { previousIndex = null, log = console.log }
     .map(spec => { delete spec.forceCurrent; return spec; })
 
     // Complete information with previous/next level links
-    .map((spec, _, list) => Object.assign(spec, computePrevNext(spec, list)));
+    .map((spec, _, list) => Object.assign(spec, computePrevNext(spec, list)))
+
+    // Complete information with forks
+    .map((spec, _, list) => {
+      const forks = list.filter(s =>
+          s.series.shortname === spec.series.shortname &&
+          s.seriesComposition === "fork" &&
+          s.forkOf === spec.shortname)
+        .map(s => s.shortname);
+      if (forks.length > 0) {
+        spec.forks = forks;
+      }
+      return spec;
+    });
   log(`Prepare initial list of specs... found ${specs.length} specs`);
 
   // Fetch additional spec info from external sources and complete the list
diff --git a/src/compute-currentlevel.js b/src/compute-currentlevel.js
index 07d78ecb..80d12623 100644
--- a/src/compute-currentlevel.js
+++ b/src/compute-currentlevel.js
@@ -9,7 +9,7 @@
  * (if needed) properties.
  *
  * By default, the current level is defined as the last level that is not a
- * delta spec, unless a level is explicitly flagged with a "forceCurrent"
+ * delta/fork spec, unless a level is explicitly flagged with a "forceCurrent"
  * property in the list of specs.
  */
 
@@ -27,9 +27,12 @@ module.exports = function (spec, list) {
 
   const current = list.reduce((candidate, curr) => {
     if (curr.series.shortname === candidate.series.shortname &&
-      !candidate.forceCurrent &&
-      curr.seriesComposition !== "delta" &&
-        (curr.forceCurrent || candidate.seriesComposition === "delta" ||
+        !candidate.forceCurrent &&
+        curr.seriesComposition !== "fork" &&
+        curr.seriesComposition !== "delta" &&
+        (curr.forceCurrent ||
+          candidate.seriesComposition === "delta" ||
+          candidate.seriesComposition === "fork" ||
           (curr.seriesVersion || "0") > (candidate.seriesVersion || "0"))) {
       return curr;
     }
diff --git a/src/compute-prevnext.js b/src/compute-prevnext.js
index 1d7fa88a..aa8172ab 100644
--- a/src/compute-prevnext.js
+++ b/src/compute-prevnext.js
@@ -22,7 +22,7 @@ module.exports = function (spec, list) {
   const level = spec.seriesVersion || "0";
 
   return list
-    .filter(s => s.series.shortname === spec.series.shortname)
+    .filter(s => s.series.shortname === spec.series.shortname && s.seriesComposition !== "fork")
     .sort((a, b) => (a.seriesVersion || "0").localeCompare(b.seriesVersion || "0"))
     .reduce((res, s) => {
       if ((s.seriesVersion || "0") < level) {
diff --git a/src/compute-shortname.js b/src/compute-shortname.js
index f236a2b9..1ad9c320 100644
--- a/src/compute-shortname.js
+++ b/src/compute-shortname.js
@@ -128,7 +128,7 @@ function computeShortname(url) {
 /**
  * Compute the shortname and level from the spec name, if possible.
  */
-function completeWithSeriesAndLevel(shortname, url) {
+function completeWithSeriesAndLevel(shortname, url, forkOf) {
   // Use latest convention for CSS specs
   function modernizeShortname(name) {
     if (name.startsWith("css3-")) {
@@ -142,22 +142,25 @@ function completeWithSeriesAndLevel(shortname, url) {
     }
   }
 
+  const seriesBasename = forkOf ?? shortname;
+  const specShortname = forkOf ? `${forkOf}-fork-${shortname}` : shortname;
+
   // Shortnames of WebGL extensions sometimes end up with digits which are *not*
   // to be interpreted as level numbers. Similarly, shortnames of ECMA specs
   // typically have the form "ecma-ddd", and "ddd" is *not* a level number.
-  if (shortname.match(/^ecma-/) || url.match(/^https:\/\/www\.khronos\.org\/registry\/webgl\/extensions\//)) {
+  if (seriesBasename.match(/^ecma-/) || url.match(/^https:\/\/www\.khronos\.org\/registry\/webgl\/extensions\//)) {
     return {
-      shortname,
-      series: { shortname }
+      shortname: specShortname,
+      series: { shortname: seriesBasename }
     };
   }
 
   // Extract X and X.Y levels, with form "name-X" or "name-X.Y".
   // (e.g. 5 for "mediaqueries-5", 1.2 for "wai-aria-1.2")
-  let match = shortname.match(/^(.*?)-(\d+)(.\d+)?$/);
+  let match = seriesBasename.match(/^(.*?)-(\d+)(.\d+)?$/);
   if (match) {
     return {
-      shortname,
+      shortname: specShortname,
       series: { shortname: modernizeShortname(match[1]) },
       seriesVersion: match[3] ? match[2] + match[3] : match[2]
     };
@@ -165,10 +168,10 @@ function completeWithSeriesAndLevel(shortname, url) {
 
   // Extract X and X.Y levels with form "nameX" or "nameXY" (but not "nameXXY")
   // (e.g. 2.1 for "CSS21", 1.1 for "SVG11", 4 for "selectors4")
-  match = shortname.match(/^(.*?)(?<!\d)(\d)(\d?)$/);
+  match = seriesBasename.match(/^(.*?)(?<!\d)(\d)(\d?)$/);
   if (match) {
     return {
-      shortname,
+      shortname: specShortname,
       series: { shortname: modernizeShortname(match[1]) },
       seriesVersion: match[3] ? match[2] + "." + match[3] : match[2]
     };
@@ -176,8 +179,8 @@ function completeWithSeriesAndLevel(shortname, url) {
 
   // No level found
   return {
-    shortname,
-    series: { shortname: modernizeShortname(shortname) }
+    shortname: specShortname,
+    series: { shortname: modernizeShortname(seriesBasename) }
   };
 }
 
@@ -186,9 +189,9 @@ function completeWithSeriesAndLevel(shortname, url) {
  * Exports main function that takes a URL (or a spec name) and returns an
  * object with a name, a shortname and a level (if needed).
  */
-module.exports = function (url) {
+module.exports = function (url, forkOf) {
   if (!url) {
     throw "No URL passed as parameter";
   }
-  return completeWithSeriesAndLevel(computeShortname(url), url);
+  return completeWithSeriesAndLevel(computeShortname(url), url, forkOf);
 }
diff --git a/src/lint.js b/src/lint.js
index 9667a9d5..a50e6918 100644
--- a/src/lint.js
+++ b/src/lint.js
@@ -15,6 +15,7 @@ function shortenDefinition(spec) {
   const short = {};
   for (const property of Object.keys(spec)) {
     if (!((property === "seriesComposition" && spec[property] === "full") ||
+        (property === "seriesComposition" && spec[property] === "fork") ||
         (property === "multipage" && !spec[property]) ||
         (property === "forceCurrent" && !spec[property]))) {
       short[property] = spec[property];
@@ -74,7 +75,8 @@ function lintStr(specsStr) {
       const next = linked.seriesNext ?
         linkedList.find(p => p.shortname === linked.seriesNext) :
         null;
-      const isLast = !next || next.seriesComposition === "delta";
+      const isLast = !next || next.seriesComposition === "delta" ||
+        next.seriesComposition === "fork";
       if (spec.forceCurrent && isLast) {
         spec.forceCurrent = false;
       }
diff --git a/test/compute-currentlevel.js b/test/compute-currentlevel.js
index c21cbfe2..8e60558a 100644
--- a/test/compute-currentlevel.js
+++ b/test/compute-currentlevel.js
@@ -8,7 +8,7 @@ describe("compute-currentlevel module", () => {
   function getSpec(options) {
     options = options || {};
     const res = {
-      shortname: (options.seriesVersion ? `spec-${options.seriesVersion}` : "spec"),
+      shortname: options.shortname ?? (options.seriesVersion ? `spec-${options.seriesVersion}` : "spec"),
       series: { shortname: "spec" },
     };
     for (const property of Object.keys(options)) {
@@ -49,6 +49,14 @@ describe("compute-currentlevel module", () => {
       spec.shortname);
   });
 
+  it("returns the name of the latest level that is not a fork spec", () => {
+    const spec = getSpec({ seriesVersion: "1" });
+    const fork = getSpec({ seriesVersion: "2", seriesComposition: "fork" });
+    assert.equal(
+      getCurrentName(spec, [spec, fork]),
+      spec.shortname);
+  });
+
   it("gets back to the latest level when spec is a delta spec", () => {
     const spec = getSpec({ seriesVersion: "1" });
     const delta = getSpec({ seriesVersion: "2", seriesComposition: "delta" });
@@ -57,6 +65,14 @@ describe("compute-currentlevel module", () => {
       spec.shortname);
   });
 
+  it("gets back to the latest level when spec is a fork spec", () => {
+    const spec = getSpec({ seriesVersion: "1" });
+    const fork = getSpec({ seriesVersion: "2", seriesComposition: "fork" });
+    assert.equal(
+      getCurrentName(fork, [spec, fork]),
+      spec.shortname);
+  });
+
   it("returns the spec name if it is flagged as current", () => {
     const spec = getSpec({ seriesVersion: "1", forceCurrent: true });
     const last = getSpec({ seriesVersion: "2" });
@@ -81,4 +97,12 @@ describe("compute-currentlevel module", () => {
       getCurrentName(spec, [spec, other]),
       spec.shortname);
   });
+
+  it("does not take forks into account", () => {
+    const spec = getSpec({ shortname: "spec-1-fork-1", seriesVersion: "1", seriesComposition: "fork" });
+    const base = getSpec({ seriesVersion: "1" });
+    assert.equal(
+      getCurrentName(spec, [spec, base]),
+      base.shortname);
+  });
 });
\ No newline at end of file
diff --git a/test/compute-shortname.js b/test/compute-shortname.js
index 15805f54..96c65984 100644
--- a/test/compute-shortname.js
+++ b/test/compute-shortname.js
@@ -105,6 +105,11 @@ describe("compute-shortname module", () => {
         () => computeInfo("https://w3c.github.io/spec4.2/"),
         /^Specification name contains unexpected characters/);
     });
+
+    it("handles forks", () => {
+      const url = "https://www.w3.org/TR/extension/";
+      assert.equal(computeInfo(url, "source-2").shortname, "source-2-fork-extension");
+    });
   });
 
 
@@ -152,6 +157,11 @@ describe("compute-shortname module", () => {
     it("preserves digits at the end of WebGL extension names", () => {
       assertSeries("https://www.khronos.org/registry/webgl/extensions/EXT_wow32/", "EXT_wow32");
     });
+
+    it("handles forks", () => {
+      const url = "https://www.w3.org/TR/the-ext/";
+      assert.equal(computeInfo(url, "source-2").series.shortname, "source");
+    });
   });
 
 
@@ -203,5 +213,10 @@ describe("compute-shortname module", () => {
     it("does not confuse digits at the end of a WebGL extension spec with a series version", () => {
       assertNoSeriesVersion("https://www.khronos.org/registry/webgl/extensions/EXT_wow32/");
     });
+
+    it("handles forks", () => {
+      const url = "https://www.w3.org/TR/the-ext/";
+      assert.equal(computeInfo(url, "source-2").seriesVersion, "2");
+    });
   });
 });
\ No newline at end of file
diff --git a/test/index.js b/test/index.js
index 977a08ef..abfd43d0 100644
--- a/test/index.js
+++ b/test/index.js
@@ -90,6 +90,18 @@ describe("List of specs", () => {
     assert.deepStrictEqual(wrong, []);
   });
 
+  it("does not have previous links for fork specs", () => {
+    const wrong = specs.filter(s =>
+      s.seriesComposition === "fork" && s.seriesPrevious);
+    assert.deepStrictEqual(wrong, []);
+  });
+
+  it("does not have next links for fork specs", () => {
+    const wrong = specs.filter(s =>
+      s.seriesComposition === "fork" && s.seriesNext);
+    assert.deepStrictEqual(wrong, []);
+  });
+
   it("has consistent series info", () => {
     const wrong = specs.filter(s => {
       if (!s.seriesPrevious) {
@@ -150,4 +162,28 @@ describe("List of specs", () => {
     const wrong = specs.filter(s => s.release && !s.release.filename);
     assert.deepStrictEqual(wrong, []);
   });
+
+  it("has a forkOf property for all fork specs", () => {
+    const wrong = specs.filter(s => s.seriesComposition === "fork" && !s.forkOf);
+    assert.deepStrictEqual(wrong, []);
+  });
+
+  it("has a fork composition level for all fork specs", () => {
+    const wrong = specs.filter(s => s.forkOf && s.seriesComposition !== "fork");
+    assert.deepStrictEqual(wrong, []);
+  });
+
+  it("only has forks of existing specs", () => {
+    const wrong = specs.filter(s => s.forkOf && !specs.find(spec => spec.shortname === s.forkOf));
+    assert.deepStrictEqual(wrong, []);
+  });
+
+  it("has consistent forks properties", () => {
+    const wrong = specs.filter(s => !!s.forks &&
+      s.forks.find(shortname => !specs.find(spec =>
+        spec.shortname === shortname &&
+        spec.seriesComposition === "fork" &&
+        spec.forkOf === s.shortname)));
+    assert.deepStrictEqual(wrong, []);
+  });
 });
diff --git a/test/lint.js b/test/lint.js
index ef7ee804..4500ca52 100644
--- a/test/lint.js
+++ b/test/lint.js
@@ -171,5 +171,16 @@ describe("Linter", () => {
         lintStr(toStr(specs)),
         toStr(["https://www.w3.org/TR/duplicate/"]));
     });
+
+    it("lints an object with a forkOf and a seriesComposition property", () => {
+      const specs = [
+        "https://www.w3.org/TR/spec-1/",
+        { "url": "https://www.w3.org/TR/spec-2/", seriesComposition: "fork", forkOf: "spec-1" }
+      ];
+      assert.equal(lintStr(toStr(specs)), toStr([
+        "https://www.w3.org/TR/spec-1/",
+        { "url": "https://www.w3.org/TR/spec-2/", forkOf: "spec-1" }
+      ]));
+    });
   });
 });
diff --git a/test/specs.js b/test/specs.js
index 0080d9ab..30245fea 100644
--- a/test/specs.js
+++ b/test/specs.js
@@ -92,7 +92,7 @@ function specs2objects(specs) {
 
 function specs2LinkedList(specs) {
   return specs2objects(specs)
-    .map(s => Object.assign({}, s, computeInfo(s.shortname || s.url)))
+    .map(s => Object.assign({}, s, computeInfo(s.shortname || s.url, s.forkOf)))
     .map((s, _, list) => Object.assign({}, s, computePrevNext(s, list)));
 }
 
@@ -159,7 +159,7 @@ describe("Input list", () => {
     it("only contains specs for which a shortname can be generated", () => {
       // Convert entries to spec objects and compute shortname
       const specsWithoutShortname = specs2objects(specs)
-        .map(spec => Object.assign({}, spec, computeInfo(spec.shortname || spec.url)))
+        .map(spec => Object.assign({}, spec, computeInfo(spec.shortname || spec.url, spec.forkOf)))
         .filter(spec => !spec.shortname);
 
       // No exception thrown? That means we're good!
@@ -172,7 +172,7 @@ describe("Input list", () => {
     it("does not have a delta spec without a previous full spec", () => {
       const fullPrevious = (spec, list) => {
         const previous = list.find(s => s.shortname === spec.seriesPrevious);
-        if (previous && previous.seriesComposition === "delta") {
+        if (previous && previous.seriesComposition && previous.seriesComposition !== "full") {
           return fullPrevious(previous, list);
         }
         return previous;
@@ -188,6 +188,12 @@ describe("Input list", () => {
       assert.strictEqual(deltaCurrent[0], undefined);
     });
 
+    it("does not have a fork spec flagged as 'current'", () => {
+      const forkCurrent = specs2LinkedList(specs)
+        .filter(s => s.forceCurrent && s.forkOf);
+      assert.strictEqual(forkCurrent[0], undefined);
+    });
+
     it("has only one spec flagged as 'current' per series shortname", () => {
       const linkedList = specs2LinkedList(specs);
       const problematicCurrent = linkedList
@@ -196,5 +202,22 @@ describe("Input list", () => {
           p.series.shortname === s.series.shortname && p.forceCurrent));
       assert.strictEqual(problematicCurrent[0], undefined);
     });
+
+    it("does not have a spec with a 'fork' seriesComposition property", () => {
+      const wrong = specs.find(s => s.seriesComposition === "fork");
+      assert.strictEqual(wrong, undefined);
+    });
+
+    it("does not have a 'delta fork' spec", () => {
+      const wrong = specs.find(s => s.forkOf && s.seriesComposition === "delta");
+      assert.strictEqual(wrong, undefined);
+    });
+
+    it("only has fork specs that reference existing specs", () => {
+      const linkedList = specs2LinkedList(specs);
+      const forkWithoutFull = linkedList.filter((s, _, list) => s.forkOf &&
+        !linkedList.find(spec => spec.shortname === s.forkOf));
+      assert.strictEqual(forkWithoutFull[0], undefined);
+    });
   });
 });