This skill enables cross-browser compatibility testing for web applications using BrowserStack, Selenium Grid, or Playwright. It tests across Chrome, Firefox, Safari, and Edge, identifying browser-specific bugs and ensuring consistent functionality. It is used when a user requests to "test browser compatibility", "run cross-browser tests", or uses the `/browser-test` or `/bt` command to assess web application behavior across different browsers and devices. The skill generates a report detailing compatibility issues and screenshots for visual verification.