The name is by way of being an acronym for "Yet Another Grand Unified Symbols Loader"... The package allows the user to access a symbol without loading the package that usually provides it; this has the advantage of avoiding the name clashes that so commonly trouble those who load symbol-packages.
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.