I'm just upgraded my wiki to 1.38.
Topic on Extension talk:TabberNeue
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Your question is quite vague, there's nothing to "fix" as this is an intentional Tracking category to help users find which pages use the Tabber parser tag {{#Tabber:}}
(many extensions do this, and MediaWiki now adds tracking categories automatically to pages in certain circumstances also. This is a helpful feature for site administrators. If you don't want these to show on pages, you might want to read Help:Categories#Hidden categories.
I know this is more than a year later, but, thank you, @TiltedCerebellum! I didn't know I could hide categories! And while it's certainly a useful category for me, as an administrator, I don't necessarily want it cluttering up the bottom of the page where categories are displayed! I've now hidden the category, and it looks great! Thanks, so much!
That's okay, we're both neglecting our emails it seems, lol. You're welcome :)
There's an option in your user prefs to show hidden categories as well, but it won't be displayed by default to users, which is nice.