diff --git a/packages/ckeditor5-dev-env/bin/translations.js b/packages/ckeditor5-dev-env/bin/translations.js
index 72c898988..aa13a6c7d 100755
--- a/packages/ckeditor5-dev-env/bin/translations.js
+++ b/packages/ckeditor5-dev-env/bin/translations.js
@@ -32,12 +32,15 @@ const tasks = {
 	 *
 	 * @returns {Promise}
 	 */
-	upload() {
-		const uploadTranslations = require( './../lib/translations/upload' );
+	async upload() {
+		const uploadPotFiles = require( './../lib/translations/upload' );
 		const getToken = require( './../lib/translations/gettoken' );
 
-		return getToken()
-			.then( credentials => uploadTranslations( credentials ) );
+		const token = await getToken();
+
+		await uploadPotFiles( {
+			token
+		} );
 	},
 
 	/**
@@ -45,12 +48,19 @@ const tasks = {
 	 *
 	 * @returns {Promise}
 	 */
-	download() {
+	async download() {
 		const downloadTranslations = require( './../lib/translations/download' );
 		const getToken = require( './../lib/translations/gettoken' );
+		const path = require( 'path' );
+
+		const token = await getToken();
 
-		return getToken()
-			.then( credentials => downloadTranslations( credentials ) );
+		const packages = new Map( getCKEditor5PackageNames().map( packageName => [
+			packageName,
+			path.join( 'packages', packageName )
+		] ) );
+
+		await downloadTranslations( { token, packages } );
 	}
 };
 
@@ -62,7 +72,13 @@ if ( !task || !tasks[ task ] ) {
 	process.exit( 1 );
 }
 
-tasks[ task ]();
+Promise.resolve()
+	.then( () => tasks[ task ]() )
+	.catch( err => {
+		console.error( err );
+
+		process.exit( 1 );
+	} );
 
 function getCKEditor5SourceFiles() {
 	const glob = require( 'glob' );
@@ -73,9 +89,15 @@ function getCKEditor5SourceFiles() {
 
 function getCKEditor5PackagePaths() {
 	const path = require( 'path' );
+
+	return getCKEditor5PackageNames()
+		.map( packageName => path.join( 'packages', packageName ) );
+}
+
+function getCKEditor5PackageNames() {
+	const path = require( 'path' );
 	const fs = require( 'fs' );
 	const ckeditor5PackagesDir = path.join( process.cwd(), 'packages' );
 
-	return fs.readdirSync( ckeditor5PackagesDir )
-		.map( packageName => path.join( 'packages', packageName ) );
+	return fs.readdirSync( ckeditor5PackagesDir );
 }
diff --git a/packages/ckeditor5-dev-env/lib/index.js b/packages/ckeditor5-dev-env/lib/index.js
index 9b8872942..b549901c5 100644
--- a/packages/ckeditor5-dev-env/lib/index.js
+++ b/packages/ckeditor5-dev-env/lib/index.js
@@ -36,12 +36,13 @@ const tasks = {
 	 *
 	 * @returns {Promise}
 	 */
-	uploadPotFiles() {
+	async uploadPotFiles() {
 		const uploadPotFiles = require( './translations/upload' );
 		const getToken = require( './translations/gettoken' );
 
-		return getToken()
-			.then( credentials => uploadPotFiles( credentials ) );
+		const token = await getToken();
+
+		await uploadPotFiles( { token } );
 	},
 
 	/**
@@ -49,12 +50,13 @@ const tasks = {
 	 *
 	 * @returns {Promise}
 	 */
-	downloadTranslations() {
+	async downloadTranslations( { packages } ) {
 		const downloadTranslations = require( './translations/download' );
 		const getToken = require( './translations/gettoken' );
 
-		return getToken()
-			.then( credentials => downloadTranslations( credentials ) );
+		const token = await getToken();
+
+		await downloadTranslations( { token, packages } );
 	}
 };
 
diff --git a/packages/ckeditor5-dev-env/lib/translations/download.js b/packages/ckeditor5-dev-env/lib/translations/download.js
index 5704ea22f..d4d751b62 100644
--- a/packages/ckeditor5-dev-env/lib/translations/download.js
+++ b/packages/ckeditor5-dev-env/lib/translations/download.js
@@ -10,92 +10,82 @@ const path = require( 'path' );
 const transifexService = require( './transifex-service' );
 const logger = require( '@ckeditor/ckeditor5-dev-utils' ).logger();
 const { cleanPoFileContent, createDictionaryFromPoFileContent } = require( '@ckeditor/ckeditor5-dev-utils' ).translations;
+const languageCodeMap = require( './languagecodemap.json' );
 
 /**
- * Downloads translations from the Transifex for each package and language.
+ * Downloads translations from the Transifex for each CF localizable package.
+ * It creates PO files out of the translations and replaces old translations with the downloaded ones.
  *
- * @param {Object} loginConfig
- * @param {String} loginConfig.token Token to the Transifex API.
+ * @param {Object} config
+ * @param {String} config.token Token to the Transifex API.
+ * @param {Map.<String,String>} config.packages A resource name -> package path map for which translations should be downloaded.
  */
-module.exports = function download( loginConfig ) {
-	return Promise.resolve()
-		.then( () => getPackageNames( loginConfig ) )
-		.then( packageNames => downloadAndReplaceTranslations( loginConfig, packageNames ) )
-		.then( () => {
-			logger.info( 'Saved all translations.' );
-		} )
-		.catch( err => {
-			logger.error( err );
-			throw err;
-		} );
-};
-
-function getPackageNames( loginConfig ) {
-	return transifexService.getResources( loginConfig )
-		.then( resources => resources.map( resource => resource.slug ) );
-}
+module.exports = async function downloadTranslations( config ) {
+	const localizablePackageNames = await getLocalizablePackages( config );
 
-function downloadAndReplaceTranslations( loginConfig, packageNames ) {
-	let promise = Promise.resolve();
+	for ( const packageName of localizablePackageNames ) {
+		const translations = await downloadPoFiles( config, packageName );
 
-	for ( const packageName of packageNames ) {
-		promise = promise.then( () => downloadAndReplaceTranslationsForPackage( loginConfig, packageName ) );
+		removeOldTranslation( config.packages.get( packageName ) );
+		saveNewTranslations( packageName, config.packages.get( packageName ), translations );
 	}
 
-	return promise;
-}
+	logger.info( 'Saved all translations.' );
+};
 
-function downloadAndReplaceTranslationsForPackage( loginConfig, packageName ) {
-	let translations;
+/**
+ * @param {Object} config
+ * @param {String} config.token Token to the Transifex API.
+ */
+async function getLocalizablePackages( config ) {
+	const packageNames = new Set( config.packages.keys() );
+	const resources = await transifexService.getResources( config );
 
-	return downloadPoFilesForPackage( loginConfig, packageName )
-		.then( _translations => { translations = _translations; } )
-		.then( () => removeOldTranslationForPackage( packageName ) )
-		.then( () => { saveTranslations( packageName, translations ); } );
+	return resources.map( resource => resource.slug )
+		.filter( packageName => packageNames.has( packageName ) );
 }
 
-function removeOldTranslationForPackage( packageName ) {
-	const del = require( 'del' );
-	const glob = path.join( process.cwd(), 'packages', packageName, 'lang', 'translations', '**' );
-
-	return del( glob );
+/**
+ * @param {String} packagePath Package path.
+ */
+function removeOldTranslation( packagePath ) {
+	fs.removeSync( getPathToTranslations( packagePath ) );
 }
 
-function downloadPoFilesForPackage( loginConfig, packageName ) {
-	const resourceDetailsPromise = transifexService.getResourceDetails( Object.assign( {}, loginConfig, {
-		slug: packageName
-	} ) );
-	let languageCodes;
-
-	const translationsForPackagePromise = resourceDetailsPromise.then( resourceDetails => {
-		languageCodes = resourceDetails.available_languages.map( languageInfo => languageInfo.code );
-
-		return Promise.all(
-			languageCodes.map( lang => downloadPoFile( loginConfig, lang, packageName ) )
-		);
-	} );
+/**
+ * Downloads translations for the given package and returns a languageCode -> translations map.
+ *
+ * @param {Object} config Configuration.
+ * @param {String} config.token Token to the Transifex API.
+ * @param {String} packageName Package name.
+ * @returns {Promise<Map.<String, Object>>}
+ */
+async function downloadPoFiles( config, packageName ) {
+	const packageOptions = Object.assign( {}, config, { slug: packageName } );
+	const resourceDetails = await transifexService.getResourceDetails( packageOptions );
 
-	return translationsForPackagePromise.then( translationsForPackage => {
-		const translationMapEntries = translationsForPackage
-			.map( ( translations, index ) => [ languageCodes[ index ], translations ] );
+	const languageCodes = resourceDetails.available_languages.map( languageInfo => languageInfo.code );
+	const translations = await Promise.all( languageCodes.map( lang => downloadPoFile( config, lang, packageName ) ) );
 
-		return new Map( translationMapEntries );
-	} );
+	return new Map( translations.map( ( languageTranslations, index ) => [
+		languageCodes[ index ],
+		languageTranslations
+	] ) );
 }
 
-function downloadPoFile( loginConfig, lang, packageName ) {
-	const config = Object.assign( {}, loginConfig, {
+async function downloadPoFile( config, lang, packageName ) {
+	const packageOptions = Object.assign( {}, config, {
 		lang,
 		slug: packageName
 	} );
 
-	return transifexService.getTranslation( config )
-		.then( data => data.content );
+	const data = await transifexService.getTranslation( packageOptions );
+
+	return data.content;
 }
 
-function saveTranslations( packageName, translations ) {
-	const languageCodeMap = require( './languagecodemap.json' );
-	let savedTranslations = 0;
+function saveNewTranslations( packageName, packagePath, translations ) {
+	let savedFiles = 0;
 
 	for ( let [ lang, poFileContent ] of translations ) {
 		if ( !isPoFileContainingTranslations( poFileContent ) ) {
@@ -108,17 +98,22 @@ function saveTranslations( packageName, translations ) {
 
 		poFileContent = cleanPoFileContent( poFileContent );
 
-		const pathToSave = path.join( process.cwd(), 'packages', packageName, 'lang', 'translations', lang + '.po' );
+		const pathToSave = path.join( getPathToTranslations( packagePath ), lang + '.po' );
 
 		fs.outputFileSync( pathToSave, poFileContent );
-		savedTranslations++;
+		savedFiles++;
 	}
 
-	logger.info( `Saved ${ savedTranslations } PO files for ${ packageName } package.` );
+	logger.info( `Saved ${ savedFiles } PO files for ${ packageName } package.` );
+}
+
+function getPathToTranslations( packagePath ) {
+	return path.join( process.cwd(), packagePath, 'lang', 'translations' );
 }
 
 function isPoFileContainingTranslations( poFileContent ) {
 	const translations = createDictionaryFromPoFileContent( poFileContent );
 
-	return Object.keys( translations ).some( key => translations[ key ] !== '' );
+	return Object.keys( translations )
+		.some( msgId => translations[ msgId ] !== '' );
 }
diff --git a/packages/ckeditor5-dev-env/lib/translations/gettoken.js b/packages/ckeditor5-dev-env/lib/translations/gettoken.js
index 43cfeb864..01a9eaccd 100644
--- a/packages/ckeditor5-dev-env/lib/translations/gettoken.js
+++ b/packages/ckeditor5-dev-env/lib/translations/gettoken.js
@@ -12,10 +12,12 @@ const inquirer = require( 'inquirer' );
  *
  * @returns {Promise.<Object>}
  */
-module.exports = function getToken() {
-	return inquirer.prompt( [ {
+module.exports = async function getToken() {
+	const { token } = await inquirer.prompt( [ {
 		type: 'password',
 		message: 'Provide the Transifex token (generate it here: https://www.transifex.com/user/settings/api/):',
 		name: 'token'
 	} ] );
+
+	return token;
 };
diff --git a/packages/ckeditor5-dev-env/tests/index.js b/packages/ckeditor5-dev-env/tests/index.js
index 27a7e7505..c62a3c8df 100644
--- a/packages/ckeditor5-dev-env/tests/index.js
+++ b/packages/ckeditor5-dev-env/tests/index.js
@@ -70,7 +70,7 @@ describe( 'dev-env/index', () => {
 
 	describe( 'releaseSubRepositories()', () => {
 		it( 'creates release for sub repositories', () => {
-			stubs.release.releaseSubRepositories.returns( Promise.resolve( { result: true } ) );
+			stubs.release.releaseSubRepositories.resolves( { result: true } );
 
 			return tasks.releaseSubRepositories( 'arg' )
 				.then( response => {
@@ -83,7 +83,7 @@ describe( 'dev-env/index', () => {
 
 	describe( 'generateChangelogForSinglePackage()', () => {
 		it( 'generates a changelog for package', () => {
-			stubs.release.generateChangelogForSinglePackage.returns( Promise.resolve( { result: true } ) );
+			stubs.release.generateChangelogForSinglePackage.resolves( { result: true } );
 
 			return tasks.generateChangelogForSinglePackage( 'arg' )
 				.then( response => {
@@ -96,7 +96,7 @@ describe( 'dev-env/index', () => {
 
 	describe( 'generateChangelogForMonoRepository()', () => {
 		it( 'generates a changelog for sub repositories', () => {
-			stubs.release.generateChangelogForMonoRepository.returns( Promise.resolve( { result: true } ) );
+			stubs.release.generateChangelogForMonoRepository.resolves( { result: true } );
 
 			return tasks.generateChangelogForMonoRepository( 123 )
 				.then( response => {
@@ -109,7 +109,7 @@ describe( 'dev-env/index', () => {
 
 	describe( 'bumpVersions()', () => {
 		it( 'updates version of dependencies', () => {
-			stubs.release.bumpVersions.returns( Promise.resolve( { result: true } ) );
+			stubs.release.bumpVersions.resolves( { result: true } );
 
 			return tasks.bumpVersions( 123 )
 				.then( response => {
@@ -133,27 +133,29 @@ describe( 'dev-env/index', () => {
 	} );
 
 	describe( 'uploadPotFiles()', () => {
-		it( 'should upload translations', () => {
-			stubs.translations.getToken.returns( Promise.resolve( { token: 'token' } ) );
+		it( 'should upload translations', async () => {
+			stubs.translations.getToken.resolves( 'token' );
 
-			return tasks.uploadPotFiles().then( () => {
-				sinon.assert.calledOnce( stubs.translations.uploadPotFiles );
-				sinon.assert.alwaysCalledWithExactly( stubs.translations.uploadPotFiles, {
-					token: 'token'
-				} );
+			await tasks.uploadPotFiles();
+
+			sinon.assert.calledOnce( stubs.translations.uploadPotFiles );
+			sinon.assert.alwaysCalledWithExactly( stubs.translations.uploadPotFiles, {
+				token: 'token'
 			} );
 		} );
 	} );
 
 	describe( 'downloadTranslations()', () => {
-		it( 'should download translations', () => {
-			stubs.translations.getToken.returns( Promise.resolve( { token: 'token' } ) );
+		it( 'should download translations', async () => {
+			stubs.translations.getToken.resolves( 'token' );
+			const packages = [];
 
-			return tasks.downloadTranslations().then( () => {
-				sinon.assert.calledOnce( stubs.translations.download );
-				sinon.assert.alwaysCalledWithExactly( stubs.translations.download, {
-					token: 'token'
-				} );
+			await tasks.downloadTranslations( { packages } );
+
+			sinon.assert.calledOnce( stubs.translations.download );
+			sinon.assert.alwaysCalledWithExactly( stubs.translations.download, {
+				token: 'token',
+				packages
 			} );
 		} );
 	} );
diff --git a/packages/ckeditor5-dev-env/tests/release-tools/utils/executeonpackages.js b/packages/ckeditor5-dev-env/tests/release-tools/utils/executeonpackages.js
index 9e6c9aa9e..331e3f484 100644
--- a/packages/ckeditor5-dev-env/tests/release-tools/utils/executeonpackages.js
+++ b/packages/ckeditor5-dev-env/tests/release-tools/utils/executeonpackages.js
@@ -22,8 +22,8 @@ describe( 'dev-env/release-tools/utils', () => {
 			sandbox.restore();
 		} );
 
-		it( 'resolves promsie when package list is empty', () => {
-			const functionToExecute = sandbox.stub().returns( Promise.resolve() );
+		it( 'resolves promise when package list is empty', () => {
+			const functionToExecute = sandbox.stub().resolves();
 
 			return executeOnPackages( new Set(), functionToExecute )
 				.then( () => {
@@ -32,7 +32,7 @@ describe( 'dev-env/release-tools/utils', () => {
 		} );
 
 		it( 'executes a function for each package found as a dependency in package.json in CWD', () => {
-			const functionToExecute = sandbox.stub().returns( Promise.resolve() );
+			const functionToExecute = sandbox.stub().resolves();
 
 			const packages = new Set( [
 				'/packages/ckeditor5-core',
@@ -78,7 +78,7 @@ describe( 'dev-env/release-tools/utils', () => {
 		} );
 
 		it( 'works fine with array', () => {
-			const functionToExecute = sandbox.stub().returns( Promise.resolve() );
+			const functionToExecute = sandbox.stub().resolves();
 
 			return executeOnPackages( [ 1, 2 ], functionToExecute )
 				.then( () => {
@@ -89,8 +89,9 @@ describe( 'dev-env/release-tools/utils', () => {
 		} );
 
 		it( 'works fine with iterator', () => {
-			const functionToExecute = sandbox.stub().returns( Promise.resolve() );
+			const functionToExecute = sandbox.stub().resolves();
 			const simpleMap = new Map( [ [ 'a', 1 ], [ 'b', 2 ] ] );
+
 			return executeOnPackages( simpleMap.keys(), functionToExecute )
 				.then( () => {
 					expect( functionToExecute.calledTwice ).to.equal( true );
diff --git a/packages/ckeditor5-dev-env/tests/translations/download.js b/packages/ckeditor5-dev-env/tests/translations/download.js
index 45277fd0f..b7d6b2f44 100644
--- a/packages/ckeditor5-dev-env/tests/translations/download.js
+++ b/packages/ckeditor5-dev-env/tests/translations/download.js
@@ -11,11 +11,9 @@ const mockery = require( 'mockery' );
 const { expect } = require( 'chai' );
 
 describe( 'download', () => {
-	let sandbox, stubs, download, resources, resourcesDetails, translations, fileContents;
+	let stubs, download, resources, resourcesDetails, translations, fileContents;
 
 	beforeEach( () => {
-		sandbox = sinon.createSandbox();
-
 		mockery.enable( {
 			useCleanCache: true,
 			warnOnReplace: false,
@@ -23,31 +21,30 @@ describe( 'download', () => {
 		} );
 
 		stubs = {
-			del: sandbox.spy( () => Promise.resolve() ),
-
 			logger: {
-				info: sandbox.stub(),
-				warning: sandbox.stub(),
-				error: sandbox.stub()
+				info: sinon.stub(),
+				warning: sinon.stub(),
+				error: sinon.stub()
 			},
 
 			fs: {
-				outputFileSync: sandbox.spy()
+				outputFileSync: sinon.stub(),
+				removeSync: sinon.stub()
 			},
 
 			translationUtils: {
-				createDictionaryFromPoFileContent: sandbox.spy( poFileContent => fileContents[ poFileContent ] ),
+				createDictionaryFromPoFileContent: sinon.stub().callsFake( poFileContent => fileContents[ poFileContent ] ),
 				cleanPoFileContent: x => x
 			},
 
 			transifexService: {
-				getResources: sandbox.spy( () => Promise.resolve( resources ) ),
-				getResourceDetails: sandbox.spy( ( { slug } ) => Promise.resolve( resourcesDetails[ slug ] ) ),
-				getTranslation: sandbox.spy( ( { lang, slug	} ) => Promise.resolve( translations[ slug ][ lang ] ) )
+				getResources: sinon.stub().callsFake( () => Promise.resolve( resources ) ),
+				getResourceDetails: sinon.stub().callsFake( ( { slug } ) => Promise.resolve( resourcesDetails[ slug ] ) ),
+				getTranslation: sinon.stub().callsFake( ( { lang, slug } ) => Promise.resolve( translations[ slug ][ lang ] ) )
 			}
 		};
 
-		sandbox.stub( process, 'cwd' ).returns( 'workspace' );
+		sinon.stub( process, 'cwd' ).returns( 'workspace' );
 
 		mockery.registerMock( '@ckeditor/ckeditor5-dev-utils', {
 			translations: stubs.translationUtils,
@@ -55,19 +52,64 @@ describe( 'download', () => {
 		} );
 
 		mockery.registerMock( 'fs-extra', stubs.fs );
-		mockery.registerMock( 'del', stubs.del );
 		mockery.registerMock( './transifex-service', stubs.transifexService );
 
 		download = require( '../../lib/translations/download' );
 	} );
 
 	afterEach( () => {
-		sandbox.restore();
+		sinon.restore();
 		mockery.disable();
 	} );
 
-	it( 'should download translations', () => {
-		mockery.registerMock( './languagecodemap.json', { 'en_AU': 'en-au' } );
+	it( 'should remove translations before downloading', async () => {
+		mockery.registerMock( './languagecodemap.json', {} );
+
+		resources = [
+			{ slug: 'ckeditor5-core' }
+		];
+
+		resourcesDetails = {
+			'ckeditor5-core': {
+				available_languages: [ {
+					code: 'pl'
+				} ]
+			}
+		};
+
+		translations = {
+			'ckeditor5-core': {
+				pl: { content: 'ckeditor5-core-pl-content' }
+			}
+		};
+
+		fileContents = {
+			'ckeditor5-core-pl-content': { save: 'save_pl' }
+		};
+
+		await download( {
+			token: 'secretToken',
+			packages: new Map( [
+				[ 'ckeditor5-core', 'foo/ckeditor5-core' ]
+			] )
+		} );
+
+		sinon.assert.calledOnce( stubs.fs.removeSync );
+		sinon.assert.calledOnce( stubs.fs.outputFileSync );
+
+		sinon.assert.calledWithExactly(
+			stubs.fs.removeSync,
+			path.join( 'workspace', 'foo', 'ckeditor5-core', 'lang', 'translations' )
+		);
+
+		sinon.assert.callOrder(
+			stubs.fs.removeSync,
+			stubs.fs.outputFileSync
+		);
+	} );
+
+	it( 'should download translations for non-empty resources', async () => {
+		mockery.registerMock( './languagecodemap.json', {} );
 
 		resources = [
 			{ slug: 'ckeditor5-core' },
@@ -82,7 +124,7 @@ describe( 'download', () => {
 			},
 			'ckeditor5-ui': {
 				available_languages: [ {
-					code: 'en_AU'
+					code: 'de'
 				} ]
 			}
 		};
@@ -92,37 +134,70 @@ describe( 'download', () => {
 				pl: { content: 'ckeditor5-core-pl-content' }
 			},
 			'ckeditor5-ui': {
-				en_AU: { content: 'ckeditor5-ui-en-content' }
+				de: { content: 'ckeditor5-ui-de-content' }
 			}
 		};
 
 		fileContents = {
-			'ckeditor5-core-pl-content': {},
-			'ckeditor5-ui-en-content': { ui: 'ui' }
+			'ckeditor5-core-pl-content': { save: 'save_pl' },
+			'ckeditor5-ui-de-content': { cancel: 'cancel_de' }
 		};
 
-		return download( { token: 'secretToken' } )
-			.then( () => {
-				sinon.assert.calledOnce( stubs.transifexService.getResources );
-				sinon.assert.calledTwice( stubs.transifexService.getResourceDetails );
-				sinon.assert.calledTwice( stubs.transifexService.getTranslation );
-				sinon.assert.calledTwice( stubs.del );
-				sinon.assert.calledOnce( stubs.fs.outputFileSync );
-
-				sinon.assert.calledWithExactly(
-					stubs.del,
-					path.join( 'workspace', 'packages', 'ckeditor5-core', 'lang', 'translations', '**' )
-				);
-
-				sinon.assert.calledWithExactly(
-					stubs.fs.outputFileSync,
-					path.join( 'workspace', 'packages', 'ckeditor5-ui', 'lang', 'translations', 'en-au.po' ),
-					'ckeditor5-ui-en-content'
-				);
-			} );
+		await download( {
+			token: 'secretToken',
+			packages: new Map( [
+				[ 'ckeditor5-core', 'foo/ckeditor5-core' ],
+				[ 'ckeditor5-ui', 'bar/ckeditor5-ui' ]
+			] )
+		} );
+
+		sinon.assert.calledTwice( stubs.fs.outputFileSync );
+
+		sinon.assert.calledWithExactly(
+			stubs.fs.outputFileSync,
+			path.join( 'workspace', 'foo', 'ckeditor5-core', 'lang', 'translations', 'pl.po' ),
+			'ckeditor5-core-pl-content'
+		);
+
+		sinon.assert.calledWithExactly(
+			stubs.fs.outputFileSync,
+			path.join( 'workspace', 'bar', 'ckeditor5-ui', 'lang', 'translations', 'de.po' ),
+			'ckeditor5-ui-de-content'
+		);
+	} );
+
+	it( 'should skip creating a resource with no translations', () => {
+		mockery.registerMock( './languagecodemap.json', {} );
+
+		resources = [
+			{ slug: 'ckeditor5-core' }
+		];
+
+		resourcesDetails = {
+			'ckeditor5-core': {
+				available_languages: [ {
+					code: 'pl'
+				} ]
+			}
+		};
+
+		translations = {
+			'ckeditor5-core': {
+				pl: { content: 'ckeditor5-core-pl-content' }
+			}
+		};
+
+		fileContents = {
+			'ckeditor5-core-pl-content': { save: 'save_pl' }
+		};
+
+		// TODO: Should it be called? It's rather a rare case anyway.
+		sinon.assert.notCalled( stubs.fs.removeSync );
+
+		sinon.assert.notCalled( stubs.fs.outputFileSync );
 	} );
 
-	it( 'should use the default language codes when the codes are missing in the languagecodemap.json file', () => {
+	it( 'should use the default language codes when the codes are missing in the languagecodemap.json file', async () => {
 		mockery.registerMock( './languagecodemap.json', {} );
 
 		resources = [
@@ -158,30 +233,38 @@ describe( 'download', () => {
 			'ckeditor5-ui-en-content': { ui: 'ui' }
 		};
 
-		// jscs:enable requireCamelCaseOrUpperCaseIdentifiers
+		await download( {
+			token: 'secretToken',
+			packages: new Map( [
+				[ 'ckeditor5-core', 'foo/ckeditor5-core' ],
+				[ 'ckeditor5-ui', 'bar/ckeditor5-ui' ]
+			] )
+		} );
 
-		return download( { token: 'secretToken' } )
-			.then( () => {
-				sinon.assert.calledWithExactly(
-					stubs.fs.outputFileSync,
-					path.join( 'workspace', 'packages', 'ckeditor5-ui', 'lang', 'translations', 'en_AU.po' ),
-					'ckeditor5-ui-en-content'
-				);
-			} );
+		sinon.assert.calledWithExactly(
+			stubs.fs.outputFileSync,
+			path.join( 'workspace', 'bar', 'ckeditor5-ui', 'lang', 'translations', 'en_AU.po' ),
+			'ckeditor5-ui-en-content'
+		);
 	} );
 
-	it( 'should report an error when something goes wrong', () => {
+	it( 'should fail with an error when the transifex service responses with an error', async () => {
 		const error = new Error();
 
-		stubs.transifexService.getResources = sandbox.spy( () => Promise.reject( error ) );
+		stubs.transifexService.getResources.rejects( error );
 
-		return download( { token: 'secretToken' } )
-			.then( () => {
-				throw new Error( 'It should throws an error' );
-			}, err => {
-				expect( err ).to.equal( error );
-				sinon.assert.calledOnce( stubs.logger.error );
-				sinon.assert.calledWithExactly( stubs.logger.error, error );
+		try {
+			await download( {
+				token: 'secretToken',
+				packages: new Map( [
+					[ 'ckeditor5-core', 'foo/ckeditor5-core' ],
+					[ 'ckeditor5-ui', 'bar/ckeditor5-ui' ]
+				] )
 			} );
+
+			throw new Error( 'Expected method to throw an error.' );
+		} catch ( err ) {
+			expect( err ).to.equal( error );
+		}
 	} );
 } );
diff --git a/packages/ckeditor5-dev-utils/lib/translations/multiplelanguagetranslationservice.js b/packages/ckeditor5-dev-utils/lib/translations/multiplelanguagetranslationservice.js
index 4faccf88b..20f54b5e9 100644
--- a/packages/ckeditor5-dev-utils/lib/translations/multiplelanguagetranslationservice.js
+++ b/packages/ckeditor5-dev-utils/lib/translations/multiplelanguagetranslationservice.js
@@ -193,7 +193,11 @@ module.exports = class MultipleLanguageTranslationService extends EventEmitter {
 		compilationAssetNames = compilationAssetNames
 			.filter( name => name.endsWith( '.js' ) );
 
-		let mainLanguage = this._mainLanguage;
+		let bundledLanguage = this._mainLanguage;
+
+		if ( this._addMainLanguageTranslationsToAllAssets ) {
+			console.log( true );
+		}
 
 		if ( compilationAssetNames.length == 0 && !this._buildAllTranslationsToSeparateFiles ) {
 			this.emit( 'error', [
@@ -203,9 +207,9 @@ module.exports = class MultipleLanguageTranslationService extends EventEmitter {
 			].join( '\n' ) );
 
 			compilationAssetNames = [];
-			mainLanguage = null;
+			bundledLanguage = null;
 		} else if ( this._buildAllTranslationsToSeparateFiles ) {
-			mainLanguage = null;
+			bundledLanguage = null;
 			compilationAssetNames = [];
 		} else if ( compilationAssetNames.length > 1 && !this._addMainLanguageTranslationsToAllAssets ) {
 			this.emit( 'error', [
@@ -216,11 +220,11 @@ module.exports = class MultipleLanguageTranslationService extends EventEmitter {
 			].join( '\n' ) );
 
 			compilationAssetNames = [];
-			mainLanguage = null;
+			bundledLanguage = null;
 		}
 
-		const otherLanguages = Array.from( this._languages )
-			.filter( lang => lang !== mainLanguage );
+		const assetLanguages = Array.from( this._languages )
+			.filter( lang => lang !== bundledLanguage );
 
 		return [
 			// Assets where translations for the main language will be added.
@@ -231,7 +235,7 @@ module.exports = class MultipleLanguageTranslationService extends EventEmitter {
 			} ) ),
 
 			// Translation assets outputted to separate translation files.
-			...this._getTranslationAssets( outputDirectory, otherLanguages )
+			...this._getTranslationAssets( outputDirectory, assetLanguages )
 		];
 	}