purge is a third-party extension; it removes untracked files as you wrote.
But ~purge~ prune is also a command of the evolve extension, that is conceptually similar to strip, as GP wrote.
But ~purge~ prune is also a command of the evolve extension, that is conceptually similar to strip, as GP wrote.
purge is not a third party extension. It is distributed along with Mercurial.