Someone (cannot find it back :() has published a script making all icons of blender visible.
API changes made it not working anymore.
Today’s blender and making the script an addon works again!
One change (!!!) needed to show the selection mark in the preferences window was needed line 1077 of …/ui/space_userpref.py had to be camouflaged by a #
Your comments (and who was the author in which page, search did not succeed)