I'm trying to find the information for the terms regarding the benefits of upgrading weapons (besides the obvious). 

Like for instance Longarms, it says it increases the "Overheat Ability Chance" but doesn't explain anywhere what that does or means.  

There is also "Critical Hit Chance" and others that should have at the very least, a tutorial written about them. 

I have searched the forums, release notes, Discord etc. I cannot find a detailed explanation or description of these in-game attributes. 

Can you guys release a glossary of terms?