`<all_urls>` is not supported

For Chrome extensions, `` matches any URL that uses a permitted scheme (`http`, `https`, `file`, or `ftp`).

`*://*/*` is the closest we can get with urlmatch but for Chrome extensions that wouldn't match `file` or `ftp` URLs (though, `ftp` is probably not supported anymore so the only difference would be `file`).

No file, test, or entry point is named. Start by locating the URL-pattern matching implementation and its tests, then compare the current `*://*/*` behavior with Chrome's `` schemes: `http`, `https`, `file`, and `ftp`. Done means an equivalent pattern matches all permitted schemes without changing existing matching behavior.

Written by the indexing model from the issue text.