Quite often I find myself on edge.launchpad.net instead of the 'usual' launchpad. It looks exactly the same as traditional launchpad, so I wonder if there is any difference. This happens usually when I go to launchpad by clicking a link on a third party website. Somehow people prefer to link to the edge subdomain of launchpad, or at least I have such impression.
So what exactly is the edge.launchpad.net? And why some people prefer it than the usual launchpad.net?
Looking for information I was always redirected to https://help.launchpad.net/LaunchpadReleases and https://help.launchpad.net/BetaTesting , but I didn't find there anything about edge. I guess it may be something like a testing environment, if yes, than how does it differ from staging.launchpad.net and qastaging.launchpad.net?