PROJ EXTRA RAND
This is a value that is randomly added to the projectile's extra according to this code in the source:
if (thisprojectile[i].extra_rand > 0) s->extra += (TRAND&thisprojectile[i].extra_rand);
This is a value that is randomly added to the projectile's extra according to this code in the source:
if (thisprojectile[i].extra_rand > 0) s->extra += (TRAND&thisprojectile[i].extra_rand);