chore: [DSYS-616] replace single BannerBase instance and update @deprecated JSDoc

[cursor]

Description

Processes the latest DSYS-616 BannerBase migration docs and applies one safe extension migration step.

Changes made:

• Updated legacy BannerBase @deprecated JSDoc to include the migration guide link.
• Replaced exactly one production usage of legacy BannerBase with MMDS BannerBase in the network connection banner.
• Updated that callsite to use class-based rounding (rounded-md) instead of legacy borderRadius prop, per migration guidance to prefer explicit MMDS APIs and styling classes.

DSYS_EPIC: DSYS-616
Processed MIGRATION_DOCS_VERSION: 79f71d38

Changelog

CHANGELOG entry: null

Related issues

Fixes: DSYS-632

Manual testing steps

1. Navigate to a state where NetworkConnectionBanner is rendered (degraded/unavailable network connection).
2. Verify banner content still renders with icon, primary text, and secondary action text.
3. Verify no React unknown-prop warnings are emitted for borderRadius from this banner path.
4. Confirm legacy BannerBase includes migration-link @deprecated JSDoc.

Migration doc discrepancies found

None.

Pre-merge author checklist

• I've followed MetaMask Contributor Docs and MetaMask Extension Coding Standards.
• I've completed the PR template to the best of my ability
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

  

[metamaskbotv2]

✨ Files requiring CODEOWNER review ✨

🎨 @MetaMask/design-system-engineers (1 files, +3 -0)

• 📁 ui/
  • 📁 components/
    • 📁 component-library/
      • 📁 banner-base/
        • 📄 banner-base.tsx +3 -0

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[metamaskbotv2]

Builds ready [066e874]

• builds: chrome, firefox
• builds (beta): chrome, firefox
• builds (flask): chrome, firefox
• builds (test): chrome, firefox
• builds (test-flask): chrome, firefox
• webpack builds: chrome, firefox
• webpack builds (beta): chrome, firefox
• webpack builds (flask): chrome, firefox
• webpack builds (test): chrome, firefox
• webpack builds (test-flask): chrome, firefox
• bundle size: Bundle Size Stats
• interaction-benchmark: Interaction Stats
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

  • background: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
  • common: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21
  • ui: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20
  • content-script: 0
  • offscreen: 0

⚡ Performance Benchmarks (Total: 🟢 18 pass · 🟡 0 warn · 🔴 0 fail)

Baseline (latest main): e4d0c5f | Date: 12/5/58221 | Pipeline: 23904801607 | Baseline logs

Interaction Benchmarks

Benchmark	chrome-browserify
loadNewAccount	🟢 [Show logs]
confirmTx	🟢 [Show logs]
bridgeUserActions	🟢 [Show logs]

📈 Results compared to the previous 5 runs on main

• ↑ bridgeUserActions/bridge_load_asset_picker: +17%

Startup Benchmarks

Benchmark	chrome-browserify	chrome-webpack	firefox-browserify	firefox-webpack
startupStandardHome	🟢 [Show logs]	🟢 [Show logs]	🟢 [Show logs]	🟢 [Show logs]
startupPowerUserHome	🟢 [Show logs]	🟢 [Show logs]	🟢 [Show logs]	🟢 [Show logs]

📈 Results compared to the previous 5 runs on main

• ↓ startupStandardHome/initialActions: -17%
• ↑ startupStandardHome/setupStore: +13%
• ↑ startupPowerUserHome/uiStartup: +13%
• ↓ startupPowerUserHome/domInteractive: -17%
• ↑ startupPowerUserHome/firstPaint: +15%
• ↑ startupPowerUserHome/backgroundConnect: +12%
• ↓ startupPowerUserHome/numNetworkReqs: -18%
• ↑ startupStandardHome/domInteractive: +17%
• ↓ startupStandardHome/initialActions: -29%
• ↓ startupStandardHome/setupStore: -12%
• ↑ startupPowerUserHome/backgroundConnect: +13%
• ↑ startupPowerUserHome/setupStore: +25%
• ↓ startupStandardHome/domInteractive: -11%
• ↑ startupStandardHome/initialActions: +67%
• ↑ startupStandardHome/setupStore: +77%
• ↑ startupPowerUserHome/domInteractive: +14%
• ↓ startupPowerUserHome/numNetworkReqs: -40%

User Journey Benchmarks

Benchmark	chrome-browserify
onboardingImportWallet	🟢 [Show logs]
onboardingNewWallet	🟢 [Show logs]
assetDetails	🟢 [Show logs]
solanaAssetDetails	🟢 [Show logs]
importSrpHome	🟢 [Show logs]
sendTransactions	🟢 [Show logs]
swap	🟢 [Show logs]

📈 Results compared to the previous 5 runs on main

• ↓ onboardingImportWallet/metricsToWalletReadyScreen: -20%
• ↓ onboardingImportWallet/doneButtonToHomeScreen: -77%
• ↑ onboardingImportWallet/openAccountMenuToAccountListLoaded: +98%
• ↓ onboardingImportWallet/total: -33%
• ↑ onboardingNewWallet/skipBackupToMetricsScreen: +15%
• ↓ onboardingNewWallet/doneButtonToAssetList: -43%
• ↓ onboardingNewWallet/total: -36%
• ↓ assetDetails/assetClickToPriceChart: -46%
• ↓ assetDetails/total: -46%
• ↓ solanaAssetDetails/assetClickToPriceChart: -40%
• ↓ solanaAssetDetails/total: -40%
• ↓ importSrpHome/openAccountMenuAfterLogin: -19%
• ↓ importSrpHome/homeAfterImportWithNewWallet: -45%
• ↓ importSrpHome/total: -39%
• ↓ swap/openSwapPageFromHome: -87%
• ↑ swap/fetchAndDisplaySwapQuotes: +28%

🌐 Dapp Page Load Benchmarks

Current Commit: 066e874 | Date: 4/2/2026

📄 Localhost MetaMask Test Dapp

Samples: 100

Summary

• pageLoadTime-> current mean value: 1.01s (±36ms) 🟡
• domContentLoaded-> current mean value: 711ms (±34ms) 🟢
• firstContentfulPaint-> current mean value: 83ms (±10ms) 🟢

📈 Detailed Results

Metric	Mean	Std Dev	Min	Max	P95	P99
pageLoadTime	1.01s	36ms	988ms	1.29s	1.03s	1.29s
domContentLoaded	711ms	34ms	686ms	974ms	724ms	974ms
firstPaint	83ms	10ms	68ms	160ms	92ms	160ms
firstContentfulPaint	83ms	10ms	68ms	160ms	92ms	160ms
largestContentfulPaint	0ms	0ms	0ms	0ms	0ms	0ms

Bundle size diffs

• background: 58 Bytes (0%)
• ui: 59 Bytes (0%)
• common: 20 Bytes (0%)