What's that gender symbol there mean?

It's a symbol that means transgender and is also used by some non-binary people to my understanding. I only really know it in the transgender sense though.

What does it mean to be a "transgender"? I found it for text, too. ⚧

It means that you physical sex (body) and that your gender do not match. So say someone who has a female body but they do not identify as a female in other ways that are not their body. Often they will have what is refereed to as dysphoria, where they feel their body is just wrong. Like their mind and soul is in a body that is not their own. (It's not just unhappiness with the body, such as if you felt you were overweight. It is a feeling of this is flat out wrong, just to be a little more specific)

So, long story short, even though you may be biologically male (or female), but you really don't feel like said gender. Correct?

Basically yes. And it's not just because of gender roles either. (Like football is something typically viewed as something men do but a female bodied person liking it doesn't automatically mean they are transgender of course) It is a bit difficult to explain how the feeling is to someone that isn't transgender, so I apologize if I am coming across as hard to understand.