Btparse is the C component of btOOL, a pair of libraries for parsing and processing BibTeX files. Its primary use is as the back-end to the Text::BibTeX library for Perl (the other half of btOOL), but there's nothing to prevent you from writing C programs using btparse -- or from writing extensions to other high-level languages using btparse as a back-end. There's even copious documentation on using the library in the "doc" directory.
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.