Browser support depends on the tooling used to build your app and the targeted ECMAScript (ES) version.
MapLibre GL JS builds target ES2019. The latest version is designed to support the most recent browsers available at the time of its release. However, there is no official documentation specifying supported browser versions.
Check browser support
You can use the supported function to test whether a browser supports MapLibre GL JS. To learn how, go to the MapLibre GL JS documentation.