diff --git a/lib/entry-points.js b/lib/entry-points.js
index e89c2ab07..ca89d1581 100644
--- a/lib/entry-points.js
+++ b/lib/entry-points.js
@@ -151206,6 +151206,20 @@ var import_fast_deep_equal = __toESM(require_fast_deep_equal());
 var semver10 = __toESM(require_semver2());
 
 // src/codeql-bundle.ts
+function getCodeQLBundleName(compressionMethod, platform2, language) {
+  const extensions = {
+    gzip: ".tar.gz",
+    zstd: ".tar.zst"
+  };
+  const extension = extensions[compressionMethod];
+  if (platform2 === void 0) {
+    return `codeql-bundle${extension}`;
+  }
+  if (language !== void 0) {
+    return `codeql-bundle-${language}-${platform2}${extension}`;
+  }
+  return `codeql-bundle-${platform2}${extension}`;
+}
 var PER_LANGUAGE_BUNDLE_NAME = /^codeql-bundle-(.+)-(?:linux64|osx64|win64)\.tar\.(?:gz|zst)$/;
 function getCodeQLBundleFromUrl(url2) {
   let assetName;
@@ -151607,6 +151621,11 @@ async function getPerLanguageBundleLanguage({
   }
   return language;
 }
+function logPerLanguageBundleFallback({ logger }, language, location) {
+  logger.warning(
+    `No per-language CodeQL bundle for '${language}' was found at ${location}, so falling back to the bundle that contains all languages. This analysis will still produce correct results, but will take longer to set up.`
+  );
+}
 
 // src/tar.ts
 var import_child_process = require("child_process");
@@ -152005,26 +152024,8 @@ var CODEQL_NIGHTLIES_REPOSITORY_NAME = "codeql-cli-nightlies";
 var CODEQL_BUNDLE_VERSION_ALIAS = ["linked", "latest"];
 var CODEQL_NIGHTLY_TOOLS_INPUTS = ["nightly", "nightly-latest"];
 var CODEQL_TOOLCACHE_INPUT = "toolcache";
-function getCodeQLBundleExtension(compressionMethod) {
-  switch (compressionMethod) {
-    case "gzip":
-      return ".tar.gz";
-    case "zstd":
-      return ".tar.zst";
-    default:
-      assertNever(compressionMethod);
-  }
-}
-function getCodeQLBundleName(compressionMethod, language) {
-  const extension = getCodeQLBundleExtension(compressionMethod);
-  const platform2 = getBundlePlatform();
-  if (platform2 === void 0) {
-    return `codeql-bundle${extension}`;
-  }
-  if (language !== void 0) {
-    return `codeql-bundle-${language}-${platform2}${extension}`;
-  }
-  return `codeql-bundle-${platform2}${extension}`;
+function getCodeQLBundleName2(compressionMethod, language) {
+  return getCodeQLBundleName(compressionMethod, getBundlePlatform(), language);
 }
 function getCodeQLActionRepository(logger) {
   if (isRunningLocalAction()) {
@@ -152447,7 +152448,7 @@ async function getCodeQLSource(toolsInput, defaultCliVersion, rawLanguages, useO
     const resolveBundleURL = (language) => getCodeQLBundleDownloadURL(
       bundleTagName,
       apiDetails,
-      getCodeQLBundleName(compressionMethod, language),
+      getCodeQLBundleName2(compressionMethod, language),
       logger
     );
     const combinedBundleURL = await resolveBundleURL();
@@ -152680,9 +152681,7 @@ async function downloadCodeQLBundle(action, source, apiDetails, tarVersion, temp
     if (bundle.kind !== "per-language" || bundle.combinedBundleURL === void 0 || asHTTPError(e)?.status !== 404) {
       throw e;
     }
-    logger.warning(
-      `No per-language CodeQL bundle for '${bundle.language}' was found at ${bundle.url}, so falling back to the bundle that contains all languages. This analysis will still produce correct results, but will take longer to set up.`
-    );
+    logPerLanguageBundleFallback(action, bundle.language, bundle.url);
     const result = await downloadCodeQL(
       {
         ...source,
@@ -152740,12 +152739,12 @@ async function getLatestNightlyBundle(action, rawLanguages, variant) {
       throw new Error("Could not find the latest nightly release.");
     }
     const assetUrl = (name) => `https://github.com/${CODEQL_NIGHTLIES_REPOSITORY_OWNER}/${CODEQL_NIGHTLIES_REPOSITORY_NAME}/releases/download/${latestRelease.tag_name}/${name}`;
-    const url2 = assetUrl(getCodeQLBundleName(compressionMethod, language));
+    const url2 = assetUrl(getCodeQLBundleName2(compressionMethod, language));
     return language === void 0 ? { kind: "combined", url: url2 } : {
       kind: "per-language",
       url: url2,
       language,
-      combinedBundleURL: assetUrl(getCodeQLBundleName(compressionMethod))
+      combinedBundleURL: assetUrl(getCodeQLBundleName2(compressionMethod))
     };
   } catch (e) {
     throw new Error(
diff --git a/src/codeql-bundle.ts b/src/codeql-bundle.ts
index 4e9f5d5de..2d262c848 100644
--- a/src/codeql-bundle.ts
+++ b/src/codeql-bundle.ts
@@ -1,4 +1,6 @@
 import { BuiltInLanguage, parseBuiltInLanguage } from "./languages";
+import { BundlePlatform } from "./platform";
+import type { CompressionMethod } from "./tar";
 
 /** Describes the contents and location of a downloadable CodeQL bundle. */
 export type CodeQLBundle =
@@ -11,6 +13,42 @@ export type CodeQLBundle =
       combinedBundleURL?: string;
     };
 
+/** A resolved download, including its bundle identity and version. */
+export interface CodeQLDownloadSource {
+  /** Distinguishes downloads from local archives and cached installations. */
+  sourceType: "download";
+  /** The bundle to download. */
+  bundle: CodeQLBundle;
+  /** The compression format of the bundle archive. */
+  compressionMethod: CompressionMethod;
+  /** Bundle version of the tools, if known. */
+  bundleVersion?: string;
+  /** Requested CLI version, if known. */
+  cliVersion?: string;
+  /** Resolved version for telemetry, independent of whether the bundle can be cached. */
+  toolsVersion: string;
+}
+
+/** Returns the exact bundle asset name for a platform and optional language. */
+export function getCodeQLBundleName(
+  compressionMethod: CompressionMethod,
+  platform: BundlePlatform | undefined,
+  language?: BuiltInLanguage,
+): string {
+  const extensions: Record<CompressionMethod, string> = {
+    gzip: ".tar.gz",
+    zstd: ".tar.zst",
+  };
+  const extension = extensions[compressionMethod];
+  if (platform === undefined) {
+    return `codeql-bundle${extension}`;
+  }
+  if (language !== undefined) {
+    return `codeql-bundle-${language}-${platform}${extension}`;
+  }
+  return `codeql-bundle-${platform}${extension}`;
+}
+
 const PER_LANGUAGE_BUNDLE_NAME =
   /^codeql-bundle-(.+)-(?:linux64|osx64|win64)\.tar\.(?:gz|zst)$/;
 
diff --git a/src/per-language-bundles.ts b/src/per-language-bundles.ts
index e4468d2f3..e0db649c7 100644
--- a/src/per-language-bundles.ts
+++ b/src/per-language-bundles.ts
@@ -131,3 +131,16 @@ export async function getPerLanguageBundleLanguage(
 
   return language;
 }
+
+/** Explains why an eligible per-language bundle is being replaced by a combined bundle. */
+export function logPerLanguageBundleFallback(
+  { logger }: ActionState<["Logger"]>,
+  language: BuiltInLanguage,
+  location: string,
+): void {
+  logger.warning(
+    `No per-language CodeQL bundle for '${language}' was found at ${location}, so ` +
+      "falling back to the bundle that contains all languages. This analysis will still " +
+      "produce correct results, but will take longer to set up.",
+  );
+}
diff --git a/src/setup-codeql.ts b/src/setup-codeql.ts
index 648435d80..58f37d638 100644
--- a/src/setup-codeql.ts
+++ b/src/setup-codeql.ts
@@ -17,7 +17,12 @@ import {
   isRunningLocalAction,
 } from "./actions-util";
 import * as api from "./api-client";
-import { CodeQLBundle, getCodeQLBundleFromUrl } from "./codeql-bundle";
+import {
+  CodeQLBundle,
+  CodeQLDownloadSource,
+  getCodeQLBundleFromUrl,
+  getCodeQLBundleName as getBundleName,
+} from "./codeql-bundle";
 import * as defaults from "./defaults.json";
 import {
   addNoLanguageDiagnostic,
@@ -35,7 +40,10 @@ import {
 import { BuiltInLanguage } from "./languages";
 import { Logger } from "./logging";
 import { getCodeQlVersionsForOverlayBaseDatabases } from "./overlay/caching";
-import { getPerLanguageBundleLanguage } from "./per-language-bundles";
+import {
+  getPerLanguageBundleLanguage,
+  logPerLanguageBundleFallback,
+} from "./per-language-bundles";
 import { getBundlePlatform } from "./platform";
 import * as tar from "./tar";
 import {
@@ -49,6 +57,8 @@ import {
 import * as util from "./util";
 import { isGoodVersion } from "./util";
 
+export type { CodeQLDownloadSource } from "./codeql-bundle";
+
 export enum ToolsSource {
   Unknown = "UNKNOWN",
   Local = "LOCAL",
@@ -64,19 +74,6 @@ const CODEQL_BUNDLE_VERSION_ALIAS: string[] = ["linked", "latest"];
 const CODEQL_NIGHTLY_TOOLS_INPUTS = ["nightly", "nightly-latest"];
 const CODEQL_TOOLCACHE_INPUT = "toolcache";
 
-function getCodeQLBundleExtension(
-  compressionMethod: tar.CompressionMethod,
-): string {
-  switch (compressionMethod) {
-    case "gzip":
-      return ".tar.gz";
-    case "zstd":
-      return ".tar.zst";
-    default:
-      util.assertNever(compressionMethod);
-  }
-}
-
 /**
  * Returns the name of the CodeQL bundle asset to download.
  *
@@ -87,16 +84,7 @@ export function getCodeQLBundleName(
   compressionMethod: tar.CompressionMethod,
   language?: BuiltInLanguage,
 ): string {
-  const extension = getCodeQLBundleExtension(compressionMethod);
-  const platform = getBundlePlatform();
-
-  if (platform === undefined) {
-    return `codeql-bundle${extension}`;
-  }
-  if (language !== undefined) {
-    return `codeql-bundle-${language}-${platform}${extension}`;
-  }
-  return `codeql-bundle-${platform}${extension}`;
+  return getBundleName(compressionMethod, getBundlePlatform(), language);
 }
 
 export function getCodeQLActionRepository(logger: Logger): string {
@@ -223,22 +211,6 @@ export function convertToSemVer(version: string, logger: Logger): string {
   return s;
 }
 
-/** A resolved download, including its bundle identity and version. */
-export interface CodeQLDownloadSource {
-  /** Distinguishes downloads from local archives and cached installations. */
-  sourceType: "download";
-  /** The bundle to download. */
-  bundle: CodeQLBundle;
-  /** The compression format of the bundle archive. */
-  compressionMethod: tar.CompressionMethod;
-  /** Bundle version of the tools, if known. */
-  bundleVersion?: string;
-  /** Requested CLI version, if known. */
-  cliVersion?: string;
-  /** Resolved version for telemetry, independent of whether the bundle can be cached. */
-  toolsVersion: string;
-}
-
 export type CodeQLToolsSource =
   | {
       codeqlTarPath: string;
@@ -1153,11 +1125,7 @@ export async function downloadCodeQLBundle(
     ) {
       throw e;
     }
-    logger.warning(
-      `No per-language CodeQL bundle for '${bundle.language}' was found at ${bundle.url}, so ` +
-        "falling back to the bundle that contains all languages. This analysis will still " +
-        "produce correct results, but will take longer to set up.",
-    );
+    logPerLanguageBundleFallback(action, bundle.language, bundle.url);
 
     const result = await downloadCodeQL(
       {