Write an automated browser test so we can generate a list of wikis where HotCat is broken.
Probably the easiest way to do this is to write a Cucumber script for Selenium (an automated browser driver) and run the test on your local machine. The script would go to a given wiki and do the following:
* Log in as Community Tech bot (or any user that doesn't care about their gadget preferences being changed)
* Load https://xxx.xxxxxx.org/wiki/Special:Preferences#mw-prefsection-gadgets
* Look for a checkbox input with id "mw-input-wpgadgets-HotCat" (I've already confirmed that the id is the same on the vast majority of wikis with HotCat)
* If the checkbox exists, check it, and click Save
* Go to Special:Random
* See if there is any element of class "hotcatlink". If so, output that wiki as working, if not, output that wiki as broken.
You can just have it write the output to your console or a text file.