Our patch system keeps a detailed changelog of sorts -- or at least something that can be thought of as one. However, we don't keep track of user-visible changes in any purticular way, and the reasons logged probably won't make much sense without a good knowladge of the internals.
...and now that I think about it, you are a member of pmdev; go to patch lister, select all of the names in "applied by", and hit "filter". Read away.
(Hopefully this hasn't been superceeded by later posts since I wrote it -- I just woke up and noticed I never hit submit last night.)
Warning: Unless otherwise stated, code is untested. Do not use without understanding. Code is posted in the hopes it is useful, but without warranty. All copyrights are relinquished into the public domain unless otherwise stated. I am not an angel. I am capable of error, and err on a fairly regular basis. If I made a mistake, please let me know (such as by replying to this node).