OptionalabortSignalOrContext: AbortSignal | BackendReadContext | nullOptionalexplicitContext: BackendReadContextThe short commit: HEAD with +uncommitted or +staged for working changes, the
reviewed commit, <range> for a range, <base>...<HEAD> for a branch, or no-commit.
Names the reviewed snapshot for the State Envelope
SNAPSHOTline, so the reviewer need not look it up.