most code writters hide the code dont know why no trade secrets justthe knowledge and kudos i guess, I know a few guys that have allowed access to Addin but XLA are complied so no these are unopenable thats the idea, but as was yes you could if allowed see them, All VBA scripts and vert complex stuff..
this level of code means next to a lot to me .. check out on search engine and see if source code is out there...