We promised at Steam Dev Days we would open source the project, so here it is:
Creating a OpenGL debugger that handles both full-stream tracing *and* state snapshotting (with compat profile support to boot!) is a surprisingly massive undertaking for ~3 devs, so please bear with us. We're knee deep in fleshing out the UI and improving the tracer/replayer to be fully compatible with GL v3.3 (4.x will be later this year). Please file bug reports on github and send us trace logs (or apitrace/vogl traces), etc. and we'll do our best to make it work with your app.
We'll be posting more instructions and our current TODO list on the wiki soon.
We're currently in the process of adding PBO support (done, testing it right now), and we've added the ability to snapshot while buffers are mapped during replaying. (Both things are needed to trace/replay/snapshot Steam 10ft.)