The latest (tip-of-tree) protocol changes frequently and may break at any time. However it captures the full capabilities of the Protocol, whereas the stable release is a subset. There is no backwards compatibility support guaranteed for the capabilities it introduces.
Latest browser_protocol.json version updated:
Date: Thu Feb 16 13:27:41 2017 -0800
Latest js_protocol.json version updated:
Date: Fri Feb 10 09:06:22 2017 -0800