Seen where? Here on meta or on a specific community? It should be discussed at meta at the community where you found it. It's curious why upper case is allowed in tags though - sounds like a good question on it's own. It could perhaps even be a conscious design decision.

About upper case: we didn't think to disallow it, and then somebody used it for a proper name. I think there was some discussion somewhere after that, but inconclusive. We should probably discuss making tags case-preserving but case-insensitive, to prevent "Tag" and "tag" coexisting in the same tag set.

Monica Cellio‭ It's actually an interesting feature, as upper/lower case can have a big significance particularly on the technical and scientific sites. As things stand currently, I don't think those sites would be overly sad if we turned everything lower case. A lot of people are used to that from SE. But I suppose there could be some clever use-cases for it at certain communities, if brought up for discussion. Accidental capitalization is a bad thing however.

I had seen it in Codidact Meta site. Sorry! I forgot to link those tags so that would be better. But main purpose of the question is : raising new question for single tag each time is completely worst idea which we mention write in a sentence. Maybe we could have a separated place where we could say "the tag is useless, or re-edit the tag if the tag's name is wrong" or similar things.. I have seen some were raising post in Software CD, Codidact Meta and some other sites. But we could inform that to mod or staff in a sentence. But when we should discuss about something then we should write that in a post (Like as : the tag A is meaningful but it would be better if we write tag Alpha reason is blah blah blah).