pkglint is for pkgsrc packages what lint(1) is for C files. It checks for various things that the used languages cannot detect, for example application-specific restrictions on certain variables. Before importing a new package or making changes to an existing package, pkglint should be run in the package's directory to check for common errors. This is the old version of pkglint. It remains because the current version is written in go and thus does not run on all pkgsrc platforms.