It’s a crotch buckle she’s undoing but she had the chest clip bit that we put on called an escape me not and she knows how to undo it x
Theres a trick for the chest clip where you put a button up shirt on them and button it over the chest clip but idk about the buckle. You can contact a cpst and ask them about it they'll know more about it. https://cert.safekids.org/find-tech
The crotch buckle or the chest clip?