This is a client for signing certificates with an ACME-server (currently only provided by letsencrypt) implemented as a relatively simple bash-script. It uses the openssl utility for everything related to actually handling keys and certificates, so you need to have that installed.
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.