Once you add the extension in either of the those browsers, an icon appears in the toolbar. Click it on to select your available public library and some educational institution ones. If your library system offers it, it will also allow you to connect to Hoopla and OverDrive.
It’s not a perfect system. Depending on which edition or version of a book you select, you will get different results. And your public library probably doesn’t carry that technical volume on an advanced biblical topic.
In any case, this is a handy way to see if your local library has a book you can check out, and sometimes it is even available as an eBook or an audiobook.
I’ve just installed the extension myself and am interested to see what it may turn up.
Software that supports biblical and theological scholarship can be pricey, and shifting from one platform to another or working with multiple ones can be even more so. In that context, “try before you buy” is a helpful principle, and Mark Hoffman has helpfully collected links to trial versions for several of the major options. Subsequent discussion on that post has noted a couple more besides.