What exactly is "Quality (Superior)" used for?

To make stuff better. it's all there in the book, equipment chapter.

Weapons get an auto-advantage on combat checks, plus increased damage (I think) and armour increases soak and reduces encumbrance (I think).

It says it adds the Superior Quality. There is a big list of all the qualities in the beginning of the equipment chapter.

Page 157 of the EotE Core Rulebook lists the effects of the Superior quality. And it lists out the exact effects that JegerGryte posted earlier.

Instead of dispersing the various weapon and armor qualities throughout the book, FFG opted to put them all in one central location for ease of reference.

The lack of specifics leads me to think that we could pretty much do anything with this that isn't already covered by another mod (within reason) like mount a blaster on a wrist guard as an unencumbered weapon.

Odd conclusion based on the wording, as it specifically states that it grants the weapon the Superior Quality , which is found where Donovan points out I was AFB so couldn't check the book.

Seiito has a point.

I always have to go back and look this up! I kinda wish it was in the mods section.