VOGL was getting much attention when it was talked about in early 2014 and then open-sourced in March of that year. The first few months were exciting with VOGL seeing plenty of commits, work on Voglperf, etc.
However, with the two year anniversary coming up I was checking out the VOGL Git repository and sadly there's been no commits since 27 April 2015. Nothing. And it's not that the program is done; the read-me still mentions the software is considered "alpha^2", etc.
I haven't been able to get any information from Valve yet on the apparent stall in VOGL's development. One can only assume that they've been preoccupied with prepping support and new tooling around Vulkan. However, there's also the sad fact that some of the key VOGL developers are no longer working at Valve like Mike Sartain, Rich Geldreich, and Peter Lohrmann.
At least though there's been a bit of activity concerning closing of issues but so far I haven't been able to find any new code branch/repository or other information pointing to the future intentions of the project. If I hear more from Valve, I'll certainly pass it along.