Maybe I'm a bit confused here, don't you have to download and extract the ZIP file each time the addon is updated? Why would you need to keep a list of the zip file contents when you have to grab the ZIP file again, and have to iterate it's extracted directory structure to do the update?
Is the listing of the ZIP file contents for backup purposes?
I also think that adding the revision number to the .toc would remove the need for a lot of these little extra files. Or, why does the updater app not just add it's own meta info into the .toc?