Mouse is Moose minus the antlers. (Moose is "A postmodern object system for Perl 5".) Moose is wonderful. Unfortunately, it's a little slow. Though significant progress has been made over the years, the compile time penalty is a non-starter for some applications. Mouse aims to alleviate this by providing a subset of Moose's functionality, faster. In particular, "has" in Moose is missing only a few expert-level features.
Binary packages can be installed with the high-level tool pkgin (which can be installed with pkg_add) or pkg_add(1) (installed by default). The NetBSD packages collection is also designed to permit easy installation from source.
The pkg_admin audit command locates any installed package which has been mentioned in security advisories as having vulnerabilities.
Please note the vulnerabilities database might not be fully accurate, and not every bug is exploitable with every configuration.
Problem reports, updates or suggestions for this package should be reported with send-pr.