A URI carries exactly one scheme: by grammar, so sha1:ssh://host?ref is not a valid shape — sha1: IS the scheme. Projectors are read-only views; transport schemes (ssh/https/be/file) imply the wire. Fetch-then-project is two commands. This is not a bug; the goal is a doc note so Verbs §"View projectors" does not read as if scheme:scheme: were possible. User clarified 2026-05-28.
The current Verbs text "all four URI slots compose; any combination is valid" reads as if a projector could stack on a transport scheme.
scheme: per URI; sha1: is the scheme, so sha1:ssh://… cannot parse.be head ssh://host?ref (refresh cache via wire), then be sha1://host?ref (cached read).sha1:, blob:, tree:, log:, …) are read-only and never open a wire; transport schemes always do.None.
A small doc edit, no code.
Nothing yet.