Browser implementation is broken

The browser implementation of this plugin uses `navigator.getBattery`:

https://developer.mozilla.org/en-US/docs/Web/API/Navigator/getBattery

> Obsolete
> This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.

Current Firefox and Edge don't support it, Chrome still seems to:
https://developer.mozilla.org/en-US/docs/Web/API/Battery_Status_API#Browser_compatibility

As far as I know there is no proper replacement.

Start by locating the browser implementation and its use of navigator.getBattery, then review the linked MDN Battery Status API compatibility information. Done would require an agreed replacement or resolution for unsupported browsers, which the issue does not currently specify.

Written by the indexing model from the issue text.