The "/" fallback checks whether the path resolves with its trailing slash dropped and answers 301 to that path, query intact, for GET and HEAD. A path that misses either way, or any other method, still gets the 404 page. Patterns ending in a {path...} wildcard accept the slash already and never reach the fallback. Pages sites are outside the forge handler and keep their own redirect toward the slash.
Ref #233. The =/mrs= rename is left as a comment on the issue.