Very few people actually manage root programs: Mozilla, Apple, Microsoft, Google, Oracle, and maybe one or two others in smaller niches. Everybody else either uses the platform's store or ships an approximation (the certificate list and some basic constraints, but missing the more complex policies implemented in mozilla::pkix) to Mozilla 's store.
That includes Debian, so probably also Ubuntu. Dunno about Red Hat but it's probably the same.
That includes Debian, so probably also Ubuntu. Dunno about Red Hat but it's probably the same.