I end up on this thread every time I forget how the commands are called, so here is an answer for all the others that are looking for it:
There are 2 commands which might help in such a case:
https://community.bistudio.com/wiki/configSourceAddonList
https://community.bistudio.com/wiki/configSourceModList
The first gives you a list of addons that define the classname/config entry you are looking for and the latter gives you a list of folders from which the corresponding PBO names were taken.