postgresql-contrib package

Hello,

I had a question about Postgres packaging. We're revamping some
documentation, and some of our features depend on pg_stat_statements and
auto_explain, and we want to guide our users to installing these if they
are not already available. I know that for a while, both pg_stat_statements
and auto_explain were available via the postgresql-contrib package, but now
it appears that this is a virtual package that just ensures installation of
the main server package? Is it no longer necessary to install contrib
separately on modern systems? I looked through the packaging wiki and faq
to try to find more details, but I did not find any info.

Thanks,
Maciek