Regression Tests?

[Edward Ardzinski]

I'm confused, trying to read old posts...

What is the "Regression Tests" documents?  Where do I locate them?

I'm using 2.6.5 on a Win XP/Home machine...right now I'm at a point where I 
want to alter the way a couple of chords are printed, probably common tricks.  
I want a 13th to just have "13" in the chord symbol rather than "9 add 13" 
(which I know is really the same thing), and want a half diminished chord to be 
printed out as a "m7b5"...

I've seen some posts about these subjects, but always mentioning 
the "Regression Tests", and that detail stumps me!

Thanks!