RLV_VERSION is supposed to follow Marine Kelley's version,
we support most 2.9.0 features, but no 2.9.20 ones. So this is correct.
RLVa_VERSION is undocumented, play pretend by matching Kitty's version
Kitty's version has no documentation about version differences
that I can find. So we're just going to pretend to be up to date.