From the introduction:
The standard combat rules in Genesys Core Rulebook cover unarmed combat in general, but some campaigns, settings, or character concepts might have an intense focus on barehanded fighting. Game Masters running games or campaigns with such characters might benefit from additional guidance, talents, and rules to provide more strategic options for fighting without weapons. The following text helps GMs run unarmed combat campaigns with Genesys Core Rulebook. The tropes and mechanics of this setting make it best suited to small parties of three or fewer PCs.
Settings that might benefit from this supplement include those evoking “street-level” superheroes, or side-scrolling “beat 'em up” or tournament “fighter” video games made famous in 1980s and 1990s arcade games. This supplement can also handle combat sports settings, such as a campaign built around boxing, mixed martial arts, or grappling tournaments. The colorful characters and over-the-top storylines of entertainment wrestling can also benefit from this supplement. Likewise, these rules can also help with settings that draw inspiration from martial arts films, birthed in the 1970s Hong Kong action movie scene, including historical and modern settings.