After performing a hg backout, the console outputs something like this:
changeset 3:a2b2d103c5ee backs out changeset 2:487a64ab45d0
The message suggests that backout metadata is recorded somewhere within Mercurial. Is this true? Given a revision, can I determine whether it was the result of a backout and determine which revision it backs out?
No, I don't think that's possible. The message you're seeing is only displayed when you run the command, there is no metadata recorded that will give you that information later. This is because "hg backout" is really nothing more than a shortcut for a series of individual steps, more details here: https://www.mercurial-scm.org/wiki/Backout#Inner_Workings
You could run those steps yourself and get the same result, and Mercurial would not know the difference.
