E2E Test Selection:
The changes are entirely within the Bridge/Swap feature area:

1. TokenSelectorItem.abTestConfig.ts (new): Defines a new A/B test (swapsSWAPS4242AbtestTokenSelectorBalanceLayout) with control/treatment variants that control whether token balance or fiat balance is shown first in the token selector, and whether to remove the ticker symbol.

2. TokenSelectorItem.tsx: Integrates the A/B test into the token selector UI component - the balance display order and format changes based on the variant. This is a UI change in the Bridge token selector used during swap/bridge flows.

3. useTrackSwapPageViewed/index.ts: Updates analytics to track both the numpad A/B test and the new token selector A/B test in active_ab_tests when the swap page is viewed.

4. useSubmitBridgeTx.ts: Forwards activeAbTests (including the new token selector A/B test) to both submitTx and submitIntent bridge controller calls for analytics/experiment tracking.

5. Test files: Unit test coverage for the above changes.

Tag selection rationale:

• SmokeTrade: Directly impacted - the token selector is used in swap/bridge flows. The A/B test changes how token balances are displayed in the token selector, which is a core part of the swap/bridge UI. Analytics tracking for swap page views is also modified.
• SmokeConfirmations: Required per SmokeTrade tag description - "When selecting SmokeTrade for swap or bridge flows, also select SmokeConfirmations (transaction confirmations are part of the flow)."

No other tags are needed - these changes are isolated to the Bridge/Swap feature area with no impact on accounts, networks, identity, snaps, ramps, or other features.

Performance Test Selection:
The changes are A/B test configuration and UI layout changes within the Bridge token selector component. While there is a UI change (balance display order), it's a minor layout change that doesn't introduce new rendering complexity, additional API calls, or significant state management changes. The changes don't affect app startup, account/network list rendering, login flows, or other performance-sensitive areas. No performance tests are warranted.