feat: add platform and install_type as MetaMetrics user traits

app/scripts/background.js

@@ -79,6 +79,7 @@ import getObjStructure from './lib/getObjStructure';
 import setupEnsIpfsResolver from './lib/ens-ipfs/setup';
 import {
   getPlatform,
+  initInstallType,
   isWebOrigin,
   shouldEmitDappViewedEvent,
 } from './lib/util';
@@ -709,6 +710,10 @@ function saveTimestamp() {
  * @returns {Promise} Setup complete.
  */
 async function initialize(backup) {
+  // Initialize install type early so it's cached for MetaMetrics user traits
+  // This is fire-and-forget - we don't await it to avoid blocking initialization
+  initInstallType();
+
   const offscreenPromise = isManifestV3 ? createOffscreen() : null;
 
   // Set up connectivity listener IMMEDIATELY for MV3 (before any awaits)

app/scripts/controllers/metametrics-controller.test.ts

@@ -1610,6 +1610,8 @@ describe('MetaMetricsController', function () {
           [MetaMetricsUserTrait.TokenSortPreference]: 'token-sort-key',
           [MetaMetricsUserTrait.PrivacyModeEnabled]: true,
           [MetaMetricsUserTrait.NetworkFilterPreference]: [],
+          [MetaMetricsUserTrait.Platform]: 'Chrome',
+          [MetaMetricsUserTrait.InstallType]: 'unknown',
         });
       });
     });

app/scripts/controllers/metametrics-controller.ts

@@ -57,7 +57,13 @@ import type {
 import { SECOND } from '../../../shared/constants/time';
 import { isManifestV3 } from '../../../shared/modules/mv3.utils';
 import { METAMETRICS_FINALIZE_EVENT_FRAGMENT_ALARM } from '../../../shared/constants/alarms';
-import { checkAlarmExists, generateRandomId, isValidDate } from '../lib/util';
+import {
+  checkAlarmExists,
+  generateRandomId,
+  getInstallType,
+  getPlatform,
+  isValidDate,
+} from '../lib/util';
 import {
   AnonymousTransactionMetaMetricsEvent,
   TransactionMetaMetricsEvent,
@@ -1435,6 +1441,8 @@ export default class MetaMetricsController extends BaseController<
       [MetaMetricsUserTrait.ProfileId]: Object.entries(
         metamaskState.srpSessionData || {},
       )?.[0]?.[1]?.profile?.profileId,
+      [MetaMetricsUserTrait.Platform]: getPlatform(),
+      [MetaMetricsUserTrait.InstallType]: getInstallType(),
     };
 
     if (!this.previousUserTraits && metamaskState.participateInMetaMetrics) {

app/scripts/lib/util.ts

@@ -2,6 +2,7 @@ import urlLib from 'url';
 import { AccessList } from '@ethereumjs/tx';
 import BN from 'bn.js';
 import { memoize } from 'lodash';
+import browser from 'webextension-polyfill';
 import {
   TransactionEnvelopeType,
   TransactionMeta,
@@ -81,6 +82,47 @@ const getPlatform = () => {
   return PLATFORM_CHROME;
 };
 
+/**
+ * Cached install type value.
+ * Possible values: 'admin', 'development', 'normal', 'sideload', 'other', 'unknown'
+ * - 'normal' means installed from official store (Chrome Web Store, Firefox Add-ons, etc.)
+ * - 'development' means loaded unpacked in developer mode
+ * - 'sideload' means installed by other software
+ * - 'admin' means installed by admin policy (enterprise)
+ * - 'unknown' means the value hasn't been fetched yet or fetch failed
+ */
+let cachedInstallType = 'unknown';
+
+/**
+ * Initializes the install type by fetching it from the browser API.
+ * This should be called early in the extension lifecycle.
+ * The result is cached and can be retrieved synchronously via getInstallType().
+ *
+ * @returns A promise that resolves to the install type string
+ */
+const initInstallType = async (): Promise<string> => {
+  try {
+    const extensionInfo = await browser.management.getSelf();
+    if (extensionInfo.installType) {
+      cachedInstallType = extensionInfo.installType;
+    }
+  } catch (error) {
+    // Silently fail - install type will remain 'unknown'
+    console.error('Error getting extension installType', error);
+  }
+  return cachedInstallType;
+};
+
+/**
+ * Returns the cached install type.
+ * Call initInstallType() first to populate the cache.
+ *
+ * @returns The install type string ('normal', 'development', 'sideload', 'admin', 'other', or 'unknown')
+ */
+const getInstallType = (): string => {
+  return cachedInstallType;
+};
+
 /**
  * Converts a hex string to a BN object
  *
@@ -159,8 +201,10 @@ export {
   checkAlarmExists,
   getChainType,
   getEnvironmentType,
+  getInstallType,
   getPlatform,
   hexToBn,
+  initInstallType,
 };
 
 // Taken from https://stackoverflow.com/a/1349426/3696652

shared/constants/metametrics.ts

@@ -565,6 +565,18 @@ export type MetaMetricsUserTraits = {
   // TODO: Fix in https://github.com/MetaMask/metamask-extension/issues/31860
   // eslint-disable-next-line @typescript-eslint/naming-convention
   rewards_referral_code_used?: string;
+  /**
+   * The platform (browser) where the extension is running.
+   * Can be 'Chrome', 'Firefox', 'Brave', 'Edge', or 'Opera'.
+   */
+  platform?: string;
+  /**
+   * The installation type of the extension.
+   * Can be 'normal' (official store), 'development', 'sideload', 'admin', 'other', or 'unknown'.
+   */
+  // TODO: Fix in https://github.com/MetaMask/metamask-extension/issues/31860
+  // eslint-disable-next-line @typescript-eslint/naming-convention
+  install_type?: string;
 };
 
 export enum MetaMetricsUserTrait {
@@ -681,6 +693,14 @@ export enum MetaMetricsUserTrait {
   HasRewardsOptedIn = 'has_rewards_opted_in',
   RewardsReferred = 'rewards_referred',
   RewardsReferralCodeUsed = 'rewards_referral_code_used',
+  /**
+   * The platform (browser) where the extension is running.
+   */
+  Platform = 'platform',
+  /**
+   * The installation type of the extension.
+   */
+  InstallType = 'install_type',
 }
 
 /**