Every host the repository claims support for has a working install path
A README that names a host it has shipped nothing for sends a reader to a command that fails. Hosts read different manifests, so support is a file at a path, not a sentence.
Observable check
for every host named in README.md or in the install documentation it links to, either the manifest that host reads is committed at the path the host reads it from, or a documented install command exists that needs no manifest; and no host is named that has neither.