Rebel's Boot Camp is a place where rebel witches/wizards get sent to. If he/she rebels and doesn't complete a course, he/she will get his/her powers taken away by Agamemnon. Jax appears in boot camp in Season 3 and reunites with Emma. Emma gets sent to boot camp for casting spells in public and Jax even risked his powers to save her.
In Neverending Summer, Jax struggled to pass the test from Agamemnon and was at risk of losing his powers forever. He gave his powers to the Witches' Council and later, he was graduated and became a full wizard.
The uniform consists of a black short sleeve shirt for the boys and a black tank top for the girls, with black pants and sneakers.