diff --git a/config/util/identifiers/subdomain.json b/config/util/identifiers/subdomain.json
index ac9fbba18d..a8e264f103 100644
--- a/config/util/identifiers/subdomain.json
+++ b/config/util/identifiers/subdomain.json
@@ -19,9 +19,7 @@
       "@type": "SubdomainExtensionBasedMapper",
       "base": { "@id": "urn:solid-server:default:variable:baseUrl" },
       "rootFilepath": { "@id": "urn:solid-server:default:variable:rootFilePath" },
-      "baseSubdomain": "www",
-      "overrideTypes_acl": "text/turtle",
-      "overrideTypes_meta": "text/turtle"
+      "baseSubdomain": "www"
     }
   ]
 }
diff --git a/config/util/identifiers/suffix.json b/config/util/identifiers/suffix.json
index 917a9e3f06..c60b37969a 100644
--- a/config/util/identifiers/suffix.json
+++ b/config/util/identifiers/suffix.json
@@ -18,9 +18,7 @@
       "@id": "urn:solid-server:default:FileIdentifierMapper",
       "@type": "ExtensionBasedMapper",
       "base": { "@id": "urn:solid-server:default:variable:baseUrl" },
-      "rootFilepath": { "@id": "urn:solid-server:default:variable:rootFilePath" },
-      "overrideTypes_acl": "text/turtle",
-      "overrideTypes_meta": "text/turtle"
+      "rootFilepath": { "@id": "urn:solid-server:default:variable:rootFilePath" }
     }
   ]
 }
diff --git a/src/storage/mapping/ExtensionBasedMapper.ts b/src/storage/mapping/ExtensionBasedMapper.ts
index c010274918..e775ca6404 100644
--- a/src/storage/mapping/ExtensionBasedMapper.ts
+++ b/src/storage/mapping/ExtensionBasedMapper.ts
@@ -1,18 +1,40 @@
 import { promises as fsPromises } from 'fs';
 import * as mime from 'mime-types';
 import type { ResourceIdentifier } from '../../ldp/representation/ResourceIdentifier';
-import { TEXT_TURTLE } from '../../util/ContentTypes';
+import { DEFAULT_CUSTOM_TYPES } from '../../util/ContentTypes';
 import { NotImplementedHttpError } from '../../util/errors/NotImplementedHttpError';
 import { joinFilePath, getExtension } from '../../util/PathUtil';
 import { BaseFileIdentifierMapper } from './BaseFileIdentifierMapper';
 import type { FileIdentifierMapperFactory, ResourceLink } from './FileIdentifierMapper';
 
+/**
+ * Supports the behaviour described in https://www.w3.org/DesignIssues/HTTPFilenameMapping.html
+ * Determines content-type based on the file extension.
+ * In case an identifier does not end on an extension matching its content-type,
+ * the corresponding file will be appended with the correct extension, preceded by $.
+ */
 export class ExtensionBasedMapper extends BaseFileIdentifierMapper {
-  private readonly types: Record<string, any>;
+  private readonly customTypes: Record<string, string>;
+  private readonly customExtensions: Record<string, string>;
 
-  public constructor(base: string, rootFilepath: string, overrideTypes = { acl: TEXT_TURTLE, meta: TEXT_TURTLE }) {
+  public constructor(
+    base: string,
+    rootFilepath: string,
+    customTypes?: Record<string, string>,
+  ) {
     super(base, rootFilepath);
-    this.types = { ...mime.types, ...overrideTypes };
+
+    // Workaround for https://github.com/LinkedSoftwareDependencies/Components.js/issues/20
+    if (!customTypes || Object.keys(customTypes).length === 0) {
+      this.customTypes = DEFAULT_CUSTOM_TYPES;
+    } else {
+      this.customTypes = customTypes;
+    }
+
+    this.customExtensions = {};
+    for (const [ extension, contentType ] of Object.entries(this.customTypes)) {
+      this.customExtensions[contentType] = extension;
+    }
   }
 
   protected async mapUrlToDocumentPath(identifier: ResourceIdentifier, filePath: string, contentType?: string):
@@ -42,7 +64,7 @@ export class ExtensionBasedMapper extends BaseFileIdentifierMapper {
     // If the extension of the identifier matches a different content-type than the one that is given,
     // we need to add a new extension to match the correct type.
     } else if (contentType !== await this.getContentTypeFromPath(filePath)) {
-      const extension = mime.extension(contentType);
+      const extension: string = mime.extension(contentType) || this.customExtensions[contentType];
       if (!extension) {
         this.logger.warn(`No extension found for ${contentType}`);
         throw new NotImplementedHttpError(`Unsupported content type ${contentType}`);
@@ -57,8 +79,10 @@ export class ExtensionBasedMapper extends BaseFileIdentifierMapper {
   }
 
   protected async getContentTypeFromPath(filePath: string): Promise<string> {
-    return this.types[getExtension(filePath).toLowerCase()] ||
-      super.getContentTypeFromPath(filePath);
+    const extension = getExtension(filePath).toLowerCase();
+    return mime.lookup(extension) ||
+      this.customTypes[extension] ||
+      await super.getContentTypeFromPath(filePath);
   }
 
   /**
diff --git a/src/storage/mapping/SubdomainExtensionBasedMapper.ts b/src/storage/mapping/SubdomainExtensionBasedMapper.ts
index 8691ca396b..3dab81ef65 100644
--- a/src/storage/mapping/SubdomainExtensionBasedMapper.ts
+++ b/src/storage/mapping/SubdomainExtensionBasedMapper.ts
@@ -1,6 +1,5 @@
 import { toASCII, toUnicode } from 'punycode/';
 import type { ResourceIdentifier } from '../../ldp/representation/ResourceIdentifier';
-import { TEXT_TURTLE } from '../../util/ContentTypes';
 import { ForbiddenHttpError } from '../../util/errors/ForbiddenHttpError';
 import { InternalServerError } from '../../util/errors/InternalServerError';
 import { NotFoundHttpError } from '../../util/errors/NotFoundHttpError';
@@ -36,8 +35,8 @@ export class SubdomainExtensionBasedMapper extends ExtensionBasedMapper {
   private readonly baseParts: { scheme: string; rest: string };
 
   public constructor(base: string, rootFilepath: string, baseSubdomain = 'www',
-    overrideTypes = { acl: TEXT_TURTLE, meta: TEXT_TURTLE }) {
-    super(base, rootFilepath, overrideTypes);
+    customTypes?: Record<string, string>) {
+    super(base, rootFilepath, customTypes);
     this.baseSubdomain = baseSubdomain;
     this.regex = createSubdomainRegexp(ensureTrailingSlash(base));
     this.baseParts = extractScheme(ensureTrailingSlash(base));
diff --git a/src/util/ContentTypes.ts b/src/util/ContentTypes.ts
index 1d0bce73dd..2fecb765e3 100644
--- a/src/util/ContentTypes.ts
+++ b/src/util/ContentTypes.ts
@@ -2,6 +2,7 @@
 export const APPLICATION_JSON = 'application/json';
 export const APPLICATION_OCTET_STREAM = 'application/octet-stream';
 export const APPLICATION_SPARQL_UPDATE = 'application/sparql-update';
+export const APPLICATION_TRIG = 'application/trig';
 export const APPLICATION_X_WWW_FORM_URLENCODED = 'application/x-www-form-urlencoded';
 export const TEXT_HTML = 'text/html';
 export const TEXT_MARKDOWN = 'text/markdown';
@@ -11,3 +12,10 @@ export const TEXT_TURTLE = 'text/turtle';
 export const INTERNAL_ALL = 'internal/*';
 export const INTERNAL_QUADS = 'internal/quads';
 export const INTERNAL_ERROR = 'internal/error';
+
+// Trig can be removed once the mime-types library is updated with the latest mime-db version
+export const DEFAULT_CUSTOM_TYPES = {
+  acl: TEXT_TURTLE,
+  meta: TEXT_TURTLE,
+  trig: APPLICATION_TRIG,
+};
diff --git a/templates/config/filesystem.json b/templates/config/filesystem.json
index 1aa123acfa..e33f1a1390 100644
--- a/templates/config/filesystem.json
+++ b/templates/config/filesystem.json
@@ -16,9 +16,7 @@
       },
       "rootFilepath": {
         "@id": "urn:solid-server:template:variable:rootFilePath"
-      },
-      "overrideTypes_acl": "text/turtle",
-      "overrideTypes_meta": "text/turtle"
+      }
     },
 
     {
diff --git a/test/unit/storage/mapping/ExtensionBasedMapper.test.ts b/test/unit/storage/mapping/ExtensionBasedMapper.test.ts
index 7be7833024..51c65f598f 100644
--- a/test/unit/storage/mapping/ExtensionBasedMapper.test.ts
+++ b/test/unit/storage/mapping/ExtensionBasedMapper.test.ts
@@ -130,6 +130,28 @@ describe('An ExtensionBasedMapper', (): void => {
       await expect(result).rejects.toThrow(NotImplementedHttpError);
       await expect(result).rejects.toThrow('Unsupported content type fake/data');
     });
+
+    it('supports custom types.', async(): Promise<void> => {
+      const customMapper = new ExtensionBasedMapper(base, rootFilepath, { cstm: 'text/custom' });
+      await expect(customMapper.mapUrlToFilePath({ path: `${base}test.cstm` }, false))
+        .resolves.toEqual({
+          identifier: { path: `${base}test.cstm` },
+          filePath: `${rootFilepath}test.cstm`,
+          contentType: 'text/custom',
+          isMetadata: false,
+        });
+    });
+
+    it('supports custom extensions.', async(): Promise<void> => {
+      const customMapper = new ExtensionBasedMapper(base, rootFilepath, { cstm: 'text/custom' });
+      await expect(customMapper.mapUrlToFilePath({ path: `${base}test` }, false, 'text/custom'))
+        .resolves.toEqual({
+          identifier: { path: `${base}test` },
+          filePath: `${rootFilepath}test$.cstm`,
+          contentType: 'text/custom',
+          isMetadata: false,
+        });
+    });
   });
 
   describe('mapFilePathToUrl', (): void => {
@@ -180,6 +202,17 @@ describe('An ExtensionBasedMapper', (): void => {
         isMetadata: false,
       });
     });
+
+    it('supports custom extensions.', async(): Promise<void> => {
+      const customMapper = new ExtensionBasedMapper(base, rootFilepath, { cstm: 'text/custom' });
+      await expect(customMapper.mapFilePathToUrl(`${rootFilepath}test$.cstm`, false))
+        .resolves.toEqual({
+          identifier: { path: `${base}test` },
+          filePath: `${rootFilepath}test$.cstm`,
+          contentType: 'text/custom',
+          isMetadata: false,
+        });
+    });
   });
 
   describe('An ExtensionBasedMapperFactory', (): void => {