wp_localize_script $handle

Question

Can anyone tell me what the "$handle" ( first parameter ) of wp_localize_script is normally used for. Thanks.

P.s.: I have no idea why but stackexchange is telling me this question dosen't meet quality standards.

Edit: When i put in my ps it accepted it so i suppose it's the length of the quesion.... if you feel like this is an unacceptable question then apologies