The store's databases is not postgres's postgres_list_databases, and a holder may serve both. A
claim's serves names the seat's verbs the module implements for the role; absent, the module's own
tools must list every verb the seat promises, which is how a module named like its seat says they
are one and the same. Registration refuses a claim naming a verb the seat never promised, and the
credential's claims carry the claim's own verbs to the runtime.
Seeded additively into the seat's row at the controller's next start; a holder must list tools of
these names (design 33 §3), so this merges after the database engine's definition does.
jschoubben