We implemented support for alpha (RGBA) cursors in the native client (and server) in bug 1122. However we didn't implement the same functionality in Web Access.
The server now also supports a second extension for alpha protocols that is easier to implement, so it might be better to focus on that.
Tested Web Access against a RHEL 8, and a Ubuntu 18.04 server with build 6364 on:
✓ Safari on macOS 10.15
✓ Firefox on Fedora 31
✓ Chrome on Windows 10
✓ IE on Windows 10
✓ Edge on Windows 10
Release notes look good. Transparency seem to work correctly.
However colors are off. Seems like the classical RGB/BGR mixup. Works fine with the native client.
Seen with Firefox on Fedora.
Ah, the red and blue channels got mixed up. Fixed upstream now: https://github.com/novnc/noVNC/commit/71bb3fdfa58954ca7b0d7be43d974316c727ff4c
Let's wait for bug 3895 to do a vendordrop.
An easy way to test this is to open a browser in the session and go to: https://css-tricks.com/using-css-cursors/#article-header-id-1
On that page there's a demo with the text "How are you feeling today" that changes the cursor to different smilies when hovered.
This has been fixed in upstream and vendordropped so it should now be tested.
I can confirm that it now works properly. Alpha is still okay, and no odd colours.
Tested with Firefox on Linux.