diff --git a/extensions/diffs/src/language-hints.test.ts b/extensions/diffs/src/language-hints.test.ts
index cdb50d0a091..982f142da5a 100644
--- a/extensions/diffs/src/language-hints.test.ts
+++ b/extensions/diffs/src/language-hints.test.ts
@@ -2,13 +2,17 @@
 import type { FileDiffMetadata } from "@pierre/diffs";
 import { describe, expect, it } from "vitest";
 import {
-  filterSupportedLanguageHints,
   normalizeDiffViewerPayloadLanguages,
+  normalizeSupportedLanguageHint,
 } from "./language-hints.js";
 
-describe("filterSupportedLanguageHints", () => {
+async function normalizeHints(values: readonly string[], options = {}) {
+  return await Promise.all(values.map((value) => normalizeSupportedLanguageHint(value, options)));
+}
+
+describe("normalizeSupportedLanguageHint", () => {
   it("keeps supported languages", async () => {
-    await expect(filterSupportedLanguageHints(["typescript", "cpp", "text"])).resolves.toEqual([
+    await expect(normalizeHints(["typescript", "cpp", "text"])).resolves.toEqual([
       "typescript",
       "cpp",
       "text",
@@ -17,7 +21,7 @@ describe("filterSupportedLanguageHints", () => {
 
   it("normalizes common aliases to base viewer languages", async () => {
     await expect(
-      filterSupportedLanguageHints(["ts", "c++", "c#", "bash", "dockerfile", "rb", "kt", "ps1"]),
+      normalizeHints(["ts", "c++", "c#", "bash", "dockerfile", "rb", "kt", "ps1"]),
     ).resolves.toEqual([
       "typescript",
       "cpp",
@@ -32,7 +36,7 @@ describe("filterSupportedLanguageHints", () => {
 
   it("keeps mainstream languages in the base viewer without the language pack", async () => {
     await expect(
-      filterSupportedLanguageHints([
+      normalizeHints([
         "ruby",
         "swift",
         "kotlin",
@@ -57,23 +61,24 @@ describe("filterSupportedLanguageHints", () => {
   });
 
   it("drops uncommon languages without the language pack", async () => {
-    await expect(filterSupportedLanguageHints(["abap"])).resolves.toEqual(["text"]);
+    await expect(normalizeSupportedLanguageHint("abap")).resolves.toBeUndefined();
   });
 
   it("keeps uncommon languages when the language pack is available", async () => {
     await expect(
-      filterSupportedLanguageHints(["abap"], { languagePackAvailable: true }),
-    ).resolves.toEqual(["abap"]);
+      normalizeSupportedLanguageHint("abap", { languagePackAvailable: true }),
+    ).resolves.toBe("abap");
   });
 
-  it("drops invalid languages and falls back to text", async () => {
-    await expect(filterSupportedLanguageHints(["not-a-real-language"])).resolves.toEqual(["text"]);
+  it("drops invalid languages", async () => {
+    await expect(normalizeSupportedLanguageHint("not-a-real-language")).resolves.toBeUndefined();
   });
 
   it("keeps valid languages when invalid hints are mixed in", async () => {
-    await expect(
-      filterSupportedLanguageHints(["typescript", "not-a-real-language"]),
-    ).resolves.toEqual(["typescript"]);
+    await expect(normalizeHints(["typescript", "not-a-real-language"])).resolves.toEqual([
+      "typescript",
+      undefined,
+    ]);
   });
 });
 
diff --git a/extensions/diffs/src/language-hints.ts b/extensions/diffs/src/language-hints.ts
index bea1ff0ca0f..47052f17479 100644
--- a/extensions/diffs/src/language-hints.ts
+++ b/extensions/diffs/src/language-hints.ts
@@ -57,13 +57,6 @@ export async function normalizeSupportedLanguageHint(
   }
 }
 
-export async function filterSupportedLanguageHints(
-  values: Iterable<string>,
-  options: { languagePackAvailable?: boolean } = {},
-): Promise<SupportedLanguages[]> {
-  return normalizeSupportedLanguageHints(values, { fallbackToText: true, ...options });
-}
-
 async function normalizeSupportedLanguageHints(
   values: Iterable<string>,
   options: { fallbackToText: boolean; languagePackAvailable?: boolean },