You know how to get full value out of weapon types your class doesn’t normally use.
Weapon Focus
You gain specialization in all weapons with which you are proficient that can be selected with Weapon Specialization.
Starfinder Core Rulebook © 2017, Paizo Inc.; Authors: Logan Bonner, Jason Bulmahn, Amanda Hamon Kunz, Jason Keeley, Robert G. McCreary, Stephen Radney-MacFarland, Mark Seifter, Owen K.C. Stephens, and James L. Sutter, with Alexander Augunas, Judy Bauer, John Compton, Adam Daigle, Crystal Frasier, Lissa Guillet, Thurston Hillman, Erik Mona, Mark Moreland, Jessica Price, F. Wesley Schneider, Amber E. Scott, and Josh Vogt.