The pkgsrc team has prepared the 50th release of their package management system, with the 2016Q1 version. I work as a Software Engineer for Joyent, where we provide Smart OS zones (also known as "containers" these days) running pkgsrc.
As someone who distributes binary packages to end users, it is imperative that those packages work as expected on the target environment and don't have any embarrassing bugs.The buildlink system ensures (amongst other things) that dependencies are correct and avoids many issues around build host pollution.We then have a number of QA scripts which analyse the generated package and ensure that the contents are accurate, RPATHs are correct, etc.It's not perfect and there are more tests we could write, but these catch a lot of mistakes that would otherwise go undetected until a user submits a bug report. We are probably one of the biggest users of pkgsrc in the world, shipping over a million package downloads per year and rising to our users, not including those distributed as part of our images or delivered from mirrors.Others for me are unprivileged support, signed packages, multi-version support, pbulk, and probably a lot of other things I've forgotten and take for granted! This is where I spend the majority of my time working on pkgsrc, and it is all performed remotely on a number of zones running in the Joyent Public Cloud.