We used to run an hourly job, but recent AIR SDKs became so big that the job would run out of memory because the server it runs on has limited memory, so we don't run the job anymore. So these days, I wait until someone complains and then run the job locally. Having more folks willing to run the job would be great.
MD5Checker downloads the file and updates it on your computer. If you submit updates as a patch or entire file, hopefully a committer will commit it for you, and if you do this often, we'll probably make you a committer and grant you rights to commit it yourself.
If you look in the history of the file, you will see where it would include beta versions. I don't remember the format and don't want to take the time to go find a revision and document how it worked, but maybe a volunteer can do that. I would trust commits from me that include beta versions. I think others would try on occasion and not quite get it right.