Topfreedom is the idea that people should be allowed to be outside without wearing a shirt if they want to. Usually, people think that only boys can go without shirts and girls have to wear a special top called a bra. But some people think that it is not fair and that girls should be able to go without a top too if they want to.
In some places, it is allowed for both boys and girls to be topless - this is called topfreedom. However, in other places, only boys are allowed to be topless because people think girls have to cover their chests because they are a private area.
Some girls feel like they should be allowed to be topless too because they see it as a way to be equal to boys. They think that there is not really any difference between boys' and girls' chests, and that both should be able to be bare if they want to.
It is important to note that topfreedom is a matter of personal choice. Some girls might feel uncomfortable being topless in public, and that is okay. Other girls might feel empowered by it, and that's okay too. It's all about what each individual is comfortable with.