The distribution hasn't got a Changelog (named something like m/^chang(es?|log)|history$/i. A Changelog helps people decide if they want to upgrade to a new version.
Add a Changelog (best named 'Changes') to the distribution. It should list at least major changes implemented in newer versions.
|buildtool not executable||
The build tool (Build.PL/Makefile.PL) is executable. This is bad because you should specify which perl you want to use while installing.
Change the permissions of Build.PL/Makefile.PL to not-executable.
This distribution is not required by another distribution by another author.
Convince / force / bribe another CPAN author to use this distribution.
|no invalid versions||
This distribution has .pm files with an invalid version.
Fix the version numbers so that version::is_lax($version) returns true.
|metayml has provides||
This distribution does not have a list of provided modules defined in META.yml.
Add all modules contained in this distribution to the META.yml field 'provides'. Module::Build does this automatically for you.
|has separate license file||
This distribution does not have a LICENSE or LICENCE file in its root directory.
This is not a critical issue. Currently mainly informative for the CPANTS authors. It might be removed later.