A path beginning with the same letters is another path, and a read-only mount
of a read-write access is still granted: the grant follows what mounts it.
Each read-write access is composed with a grant: the module's containers that
mount its path and the account its tools run as (the operator's, or the module's
own under ADR 0259 §8); that runtime restarts on the access, so it holds a group
the engine put its account in. A read access grants nothing. Sent only to an
engine whose statement says GrantContract (4), since an older one refuses the
field. Pins the node-engine at the branch that reads it.
jschoubben