What happened to the "Solved" Category Tag?

I see some topics are in the “Solved” category, but when I try to change the category of my topic, the “Solved” option doesn’t show up. Can someone explain why?

It just changed to “solved”. The topic, I mean. I think that only moderators could do that.

Apparently so. I guess they moved that to mod access only.

Only mods and admins can access those, the admins prob made a site setting where the solved category will be private.