Users should be able to toggle experimental features on/off in the WebKit nightlies. This would allow them the ability to test out new features and see progress in actively developed features, without having to wait for them to be stable enough to be enabled by default. Adding this as a master bug to track work and ideas.
We could have WebKit modify Safari's Develop menu to provide additional items to toggle when running a nightly. Safari provides an "Enable WebGL" item, we could inject more items next to it.
<rdar://problem/13724780>
If this bug was for the macOS port, I think this is fixed for MiniBrowser/Safari, since we now have a menu for experimental features. We also have such a menu on iOS/Safari.