16. Heart of Mine - Firefox AK
In 2009 the Mozilla Foundation, which had been slowly consolidating the various projects whose codebases they had taken responsibility for in 2003 at their inception, hit a crossroads. A schism was developing within their development community, with several key members finding themselves increasingly at odds with the direction the foundation was taking. A split threatened between, on the one hand, the majority who felt that streamlining the number of Mozilla projects would not just allow but was absolutely requesite for a fully open-source codebase to be maintained in the far more dynamic environment that was Web 2.0 and the emergent 'internet of things', and, on the other hand, those who really, really liked steel drums. Like, really liked steel drums.
In order to allow for both these approaches the Mozilla Foundation officially created Firefox AK, a fork of the Firefox project that aimed to allow users a completely customisable open-source browsing experience, that also featured steel drums.
I've been a regular user of the nightly builds of this fork since 2010 when I discovered malamute saloon on MySpace. He uploaded two songs - Malamute 1 and Malamute 3 - along with a picture of an alaskan malamute, but I found both songs lacking in functionality under the version of Firefox I was running at the time, so I switched to Firefox AK. Generic libraries that allowed for steel drums just couldn't match the dedicated native support that Firefox AK afforded the serious power user, who also really, really liked steel drums.
Not only is Heart of Mine my 16th best song of 2016, it's also a brilliant example of the real power and agility of open-source development. Richard Stallman would be proud.