Changes/fixes:
- Implemented support for CSS caret-color.
- Implemented support for un-prefixed ::selection CSS pseudo-element styling.
- Fixed another potential crashing scenario in ResizeObservers.
- Fixed several crashes in the DOM Fetch API.
- Fixed a crash in table pagination.
- Security issues fixed: CVE-2020-15680 (VG-VD-20-115) and several memory safety hazards.
- Unified XUL Platform Mozilla Security Patch Summary: 1 fixed, 2 defense-in-depth, 12 not applicable.