It's an just empty folder.
Yes, it appears after installing any of our products, because we have a diagnostic version of the Addon Manager that we send to users to troubleshoot specific issues. The normal version doesn't log anything, but the folder is created anyway, because of a 3rd party library we use to do logging, that creates that folder just by being included, even if nothing is actually logged into.
It's of course entirely harmless, and nobody is writing anything into it, which means there's no processing time lost to log or disk space taken, not in the normal version of the Addon Manager at least.
