So there's only one comment that gives the impression that there's some kind of troll going on. Just to let you know: It actually works, nothing fishy just someone posting the direct link to the app that's exposed via their update Api.
There's no activation or anything, it will just take you straight into the app.
Their clear wish is for this to be invite only. I agree that their 'security' should probably better if they want to protec themselves against certain types of people, but your argument is akin to justifying robbing a house of its contents because it was only locked up with no alarm and you had to break one window to get in.
No, my argument is not akin to that because piracy is not akin to theft. Downloading the beta from a public URL is not depriving Github of anything or breaking anything of theirs, whereas if I broke a window to steal something I've left the owner with a broken window and deprived them of the contents.
Yet on HN there have been numerous 'security breaches' defended solely due to the fact that the data was accessible via a public URL and if they wanted it secured they should have done better.
There's no activation or anything, it will just take you straight into the app.