Disable WebGL
WebGL sure seems like it can be used to extract a whole lot of capability info about your video card.. Most modern cards should have all the capabilities, so maybe it isn't as bad as it looks, but who knows?
If nothing else, WebGL may be usable to fingerprint rendering performance.
We may need another panopticlick study to be sure.
To upload designs, you'll need to enable LFS and have admin enable hashed storage. More information