CREATE/DROP ROLE transactional? GRANT/REVOKE?

Hi. Perhaps I missed it in the doc (e.g. [1]), but are DDLs around ROLEs
and GRANTs transactional?

Since I'm creating many ROLEs and making many GRANTs, based info I read
from PostgreSQL itself (in pg_catalog and elsewhere), should everything be
in a single transaction?

FWIW, I come from Oracle (where DDL is non-transactional and an implicit
COMMIT), and SQLite (where ROLEs and GRANTs don't apply), thus this perhaps
silly question.

I'm already aware that SCHEMAs, TABLEs, etc... are transactionally created.
But given that ROLEs are cluster-wide, and the doc on DDLs say nothing, I
prefer to ask.

Thanks, --DD

[1]: https://www.postgresql.org/docs/current/sql-droprole.html