Street Fighting
Skill, Combat
Skilled brawling: the character is proficient at fist-fighting instead of taking the non-proficiency penalty that plain Brawling carries.
From the book
Street Fighting is brawling done with skill. Where the untrained brawler takes the standard non-proficiency penalty on every attack, a street fighter is proficient at fighting with the fists. The book stresses that it is a different thing from Boxing or Wrestling, both in style and in how effective it is.
It costs 500 XP. Like all combat skills it takes 1-3 months to develop, and characters outside the fighting professions need a qualified instructor.