How do I restore the tab across the bottom of the forum that indicates what everything on the forum means?

The tab that says what each color represents and the like. I accidentally hit the "x" button.

thanks.

On the forum pages there is a link near the top named "My Settings". It's amongst the other links "My Posts", "My Suggestions", and "Help".

In those settings (which is NOT your account settings) it has a setting named:
"Show topic categories key"

Because you have disabled it, the setting will be "no". Set it to "yes" to show the topic categories.

This means you can disable there, too.

Thanks, I was looking for that in the settings I must have gone right past it, when I was updating going to first page of a post instead of the last. Now I feel dumb for missing it.

Personally, there's something about the forum settings that makes them appear inscrutable to me. I struggled to find that setting when writing that post, and when I did find it I still didn't know the name for it. I had to go back and copy/paste it into the post. What stood out to me was the "no" popup menu button, probably because having that instead of a checkbox is really odd to me.