Synergy has been a bit odd in recent years. It doesn't seem like a particularly large or complex piece of software, and many projects that seem to be of similar scope are things maintained in the spare time of a few developers. It has long been stable, and it isn't clear that drastic improvements in it have been made, or even need to be made.
Yet Synergy appears to have a corporation behind it (Synergy Si) that only appears to work on Synergy. They have an office, and apparently provide free meals, Google-style 20% projects, and a variety of other perks. They're apparently hiring. They even offer stock options, despite my being rather bewildered at where the opportunity for growth is.
I donated years ago, and found myself occasionally receiving emails that just didn't make sense, making the whole operation sound giant. If they were working on other projects, too, but it seems like all they do is work on Synergy.