--- a/toolkit/components/extensions/Extension.jsm
+++ b/toolkit/components/extensions/Extension.jsm
@@ -130,39 +130,16 @@ function validateThemeManifest(manifestP
   for (let propName of manifestProperties) {
     if (propName != "theme" && !allowedThemeProperties.includes(propName)) {
       invalidProps.push(propName);
     }
   }
   return invalidProps;
 }
 
-/**
- * Classify an individual permission from a webextension manifest
- * as a host/origin permission, an api permission, or a regular permission.
- *
- * @param {string} perm  The permission string to classify
- *
- * @returns {object}
- *          An object with exactly one of the following properties:
- *          "origin" to indicate this is a host/origin permission.
- *          "api" to indicate this is an api permission
- *                (as used for webextensions experiments).
- *          "permission" to indicate this is a regular permission.
- */
-function classifyPermission(perm) {
-  let match = /^(\w+)(?:\.(\w+)(?:\.\w+)*)?$/.exec(perm);
-  if (!match) {
-    return {origin: perm};
-  } else if (match[1] == "experiments" && match[2]) {
-    return {api: match[2]};
-  }
-  return {permission: perm};
-}
-
 const LOGGER_ID_BASE = "addons.webextension.";
 const UUID_MAP_PREF = "extensions.webextensions.uuids";
 const LEAVE_STORAGE_PREF = "extensions.webextensions.keepStorageOnUninstall";
 const LEAVE_UUID_PREF = "extensions.webextensions.keepUuidOnUninstall";
 
 const COMMENT_REGEXP = new RegExp(String.raw`
     ^
     (
@@ -453,16 +430,39 @@ this.ExtensionData = class {
           resolve(JSON.parse(text));
         } catch (e) {
           reject(e);
         }
       });
     });
   }
 
+  /**
+   * Classify an individual permission from a webextension manifest
+   * as a host/origin permission, an api permission, or a regular permission.
+   *
+   * @param {string} perm  The permission string to classify
+   *
+   * @returns {object}
+   *          An object with exactly one of the following properties:
+   *          "origin" to indicate this is a host/origin permission.
+   *          "api" to indicate this is an api permission
+   *                (as used for webextensions experiments).
+   *          "permission" to indicate this is a regular permission.
+   */
+  classifyPermission(perm) {
+    let match = /^(\w+)(?:\.(\w+)(?:\.\w+)*)?$/.exec(perm);
+    if (!match) {
+      return {origin: perm};
+    } else if (match[1] == "experiments" && match[2]) {
+      return {api: match[2]};
+    }
+    return {permission: perm};
+  }
+
   // This method should return a structured representation of any
   // capabilities this extension has access to, as derived from the
   // manifest.  The current implementation just returns the contents
   // of the permissions attribute, if we add things like url_overrides,
   // they should also be added here.
   get userPermissions() {
     if (this.type !== "extension") {
       return null;
@@ -582,17 +582,17 @@ this.ExtensionData = class {
         if (perm === "geckoProfiler") {
           const acceptedExtensions = Services.prefs.getStringPref("extensions.geckoProfiler.acceptedExtensionIds", "");
           if (!acceptedExtensions.split(",").includes(id)) {
             this.manifestError("Only whitelisted extensions are allowed to access the geckoProfiler.");
             continue;
           }
         }
 
-        let type = classifyPermission(perm);
+        let type = this.classifyPermission(perm);
         if (type.origin) {
           let matcher = new MatchPattern(perm, {ignorePath: true});
 
           perm = matcher.pattern;
           originPermissions.add(perm);
         } else if (type.api) {
           apiNames.add(type.api);
         }
@@ -1597,17 +1597,17 @@ this.Extension = class extends Extension
   }
 
   get name() {
     return this.manifest.name;
   }
 
   get optionalOrigins() {
     if (this._optionalOrigins == null) {
-      let origins = this.manifest.optional_permissions.filter(perm => classifyPermission(perm).origin);
+      let origins = this.manifest.optional_permissions.filter(perm => this.classifyPermission(perm).origin);
       this._optionalOrigins = new MatchPatternSet(origins, {ignorePath: true});
     }
     return this._optionalOrigins;
   }
 };
 
 this.Langpack = class extends ExtensionData {
   constructor(addonData, startupReason) {