Thanks for this check. I have fixed the last one. And also the last Warning (line 410), it was an empty section. But I don't understand the other warnings. (plus my podchecker for perl v5.28.2 does not show these warnings). this is the context fro one of those:

=head2 perl2yaml($perlvar, $optional_paramshashref)

Given an input C<$perlvar> (which can be a simple scalar or
a nested data structure, but not an object), it will return
the equivalent YAML string. In C<$optional_paramshashref>
one can specify whether to escape unicode with
C<'escape-unicode'=E<gt>1>. Prettify is not supported yet.
The output can fed to L<Data::Roundtrip::yaml2perl>
for getting the Perl variable back.
[download]

also, do you have an opinion about having function names with params? I don't like it when I read a manual and it mentions only sub names. So I made it very explicit what it takes in