Check: uninstall.php existence

[threadi]

Would it also be possible to add a check whether the uninstall.php exists? Unfortunately, many plugins forget this routine that should clean up after them. Checking for its presence should help to draw more attention to it.

[swissspidy]

How would you expect this to work? Not every plugin adds data that needs to be cleaned up.

Also note that register_uninstall_hook exists too.

[threadi]

The hook has its disadvantages, as described here: https://developer.wordpress.org/reference/functions/register_uninstall_hook/

Both methods are described in the manual: https://developer.wordpress.org/plugins/plugin-basics/uninstall-methods/

Couldn't you check both and if neither is available, at least display a warning?