It is a style of music, and a style of dressing.
The music is generally made up of 'beatdowns'.
It originated in Northern California, and is associated with hardcore. Also with dinocore.
The style of dressing is close to hardcore: camo shorts, basketball shorts, levis, band shirts, baller caps, vans.
Gauged ears generally go with the look.
Brocore in Southern California refers to something completely different in style, in that case it means like BMX/MX bros. With dickies and high socks. Thing metal melisha.
SharkPunch is such a good joke brocore band.