I recently saw something and I’m confused

Okay, the last time I asked a question like this it got deleted because it was mistaken for a question with ulterior motives, which I completely understand, I messed up by not being specific enough, so I just wanted to preface this by insuring you that this is a genuine question from someone seeking a genuine response.

So, I’m gender fluid and I’ve been trying to explore my sexuality, when I stumbled upon something that I remember experiencing in high school a few years ago that at the time I didn’t understand, and to be honest still don’t. Basically some of the other students said that they identified as a cat. And they wanted people to recognize that seemingly in the same way students in the LGBTQ+ community advocated for recognition.

So, I’m confused. I recently came across someone else who identified as an animal, I think it was a cat or a dog. They had like, a rainbow shirt and stuff like that, so my question is, is this a part of the LGBTQ+ community? I’m trying to broaden my knowledge of this community and I don’t wanna accidentally exclude anyone. Is this a branch of our community that I was just unaware of, or is this something else?