Rated 4 out of 5 stars

I've tested this add-on and it works for TB 3.0.

What you need to do to get it working until an official update is available is download the extension, open the xpi file with a zip utility (7-zip worked for me although if you use a different software, you may have to change the extension from xpi to zip first, unzip, edit the necessary file, rezip and set extension back to xpi.

The file you need to edit within the xpi archive is called install.rdf. The max version is set to '3.0a1'. You need to edit that value to remove the 'a1' so that it is simply '3.0'

Once you've edited the install.rdf file within the xpi archive, then install it manually from the add-on window. After installing, add it back to your toolbar using the view menu.

Hopefully the author will provide an official update soon.