feat: add support for Firefox data collection permissions

packages/wxt/src/core/resolve-config.ts

@@ -226,6 +226,7 @@ export async function resolveConfig(
     userConfigMetadata: userConfigMetadata ?? {},
     alias,
     experimental: defu(mergedConfig.experimental, {}),
+    suppressWarnings: mergedConfig.suppressWarnings ?? {},
     dev: {
       server: devServerConfig,
       reloadCommand,

packages/wxt/src/core/utils/manifest.ts

@@ -118,6 +118,20 @@ export async function generateManifest(
       ? undefined
       : versionName;
 
+  // Warn if building for Firefox without data_collection_permissions
+  if (
+    wxt.config.browser === 'firefox' &&
+    !userManifest.browser_specific_settings?.gecko
+      ?.data_collection_permissions &&
+    !wxt.config.suppressWarnings?.firefoxDataCollection
+  ) {
+    wxt.logger.warn(
+      'Firefox requires `data_collection_permissions` for new extensions from November 3, 2025. Existing extensions are exempt for now.\n' +
+        'For more details, see: https://extensionworkshop.com/documentation/develop/firefox-builtin-data-consent/\n' +
+        'To suppress this warning, add `firefoxDataCollection: true` to `suppressWarnings` in your wxt config.\n',
+    );
+  }
+
   addEntrypoints(manifest, entrypoints, buildOutput);
 
   if (wxt.config.command === 'serve') addDevModeCsp(manifest);

packages/wxt/src/core/utils/testing/fake-objects.ts

@@ -305,6 +305,7 @@ export const fakeResolvedConfig = fakeObjectCreator<ResolvedConfig>(() => {
     hooks: {},
     vite: () => ({}),
     plugins: [],
+    suppressWarnings: {},
   };
 });
 

packages/wxt/src/types.ts

@@ -131,6 +131,22 @@ export interface InlineConfig {
    * object or promise.
    */
   manifest?: UserManifest | Promise<UserManifest> | UserManifestFn;
+  /**
+   * Suppress specific warnings during the build process.
+   *
+   * @example
+   * ```ts
+   * export default defineConfig({
+   *   suppressWarnings: {
+   *     firefoxDataCollection: true,
+   *   },
+   * })
+   * ```
+   */
+  suppressWarnings?: { firefoxDataCollection?: boolean } & Record<
+    string,
+    boolean
+  >;
   /**
    * Configure browser startup. Options set here can be overridden in a `web-ext.config.ts` file.
    */
@@ -838,6 +854,39 @@ export type ResolvedPerBrowserOptions<T, TOmitted extends keyof T = never> = {
     : T[key];
 } & { [key in TOmitted]: T[key] };
 
+/**
+ * Firefox data collection permission types for personal data.
+ * See: https://extensionworkshop.com/documentation/develop/firefox-builtin-data-consent/#specifying-data-types
+ */
+export type FirefoxDataCollectionType =
+  | 'locationInfo'
+  | 'browsingActivity'
+  | 'websiteContent'
+  | 'websiteActivity'
+  | 'searchTerms'
+  | 'bookmarksInfo'
+  | 'healthInfo'
+  | 'contactInfo'
+  | 'socialInfo'
+  | (string & {});
+
+/**
+ * Firefox data collection permissions configuration.
+ * See: https://extensionworkshop.com/documentation/develop/firefox-builtin-data-consent/#specifying-data-types
+ */
+export interface FirefoxDataCollectionPermissions {
+  /**
+   * Required data collection permissions. Users must opt in to use the extension.
+   * Can include personal data types or "none" to explicitly indicate no data collection.
+   */
+  required?: Array<FirefoxDataCollectionType | 'none'>;
+  /**
+   * Optional data collection permissions. Users can opt in after installation.
+   * Can include personal data types or "technicalAndInteraction" (which can only be optional).
+   */
+  optional?: Array<FirefoxDataCollectionType | 'technicalAndInteraction'>;
+}
+
 /**
  * Manifest customization available in the `wxt.config.ts` file. You cannot configure entrypoints
  * here, they are configured inline.
@@ -873,6 +922,11 @@ export type UserManifest = {
       strict_min_version?: string;
       strict_max_version?: string;
       update_url?: string;
+      /**
+       * Firefox data collection permissions configuration.
+       * See: https://extensionworkshop.com/documentation/develop/firefox-builtin-data-consent/#specifying-data-types
+       */
+      data_collection_permissions?: FirefoxDataCollectionPermissions;
     };
     gecko_android?: {
       strict_min_version?: string;
@@ -1355,6 +1409,13 @@ export interface ResolvedConfig {
    */
   alias: Record<string, string>;
   experimental: {};
+  /**
+   * List of warning identifiers to suppress during the build process.
+   */
+  suppressWarnings: { firefoxDataCollection?: boolean } & Record<
+    string,
+    boolean
+  >;
   dev: {
     /** Only defined during dev command */
     server?: {