SO, it appears to only target Google Chrome and Apple's Safari browsers. was the Open Source Chromium (and derivatives), or Firefox also affected?
Well, these are the 11 vulnerabilities:
CVE-2020-6418 - Chrome Vulnerability in TurboFan (fixed February 2020)
CVE-2020-0938 - Font Vulnerability on Windows (fixed April 2020)
CVE-2020-1020 - Font Vulnerability on Windows (fixed April 2020)
CVE-2020-1027 - Windows CSRSS Vulnerability (fixed April 2020)
CVE-2020-15999 - Chrome Freetype heap buffer overflow
CVE-2020-17087 - Windows heap buffer overflow in cng.sys
CVE-2020-16009 - Chrome type confusion in TurboFan map deprecation
CVE-2020-16010 - Chrome for Android heap buffer overflow
CVE-2020-27930 - Safari arbitrary stack read/write via Type 1 fonts
CVE-2020-27950 - iOS XNU kernel memory disclosure in mach message trailers
CVE-2020-27932 - iOS kernel type confusion with turnstiles
Looks to me, like Firefox wasn't affected.
As for Chromium...can't tell. I don't know how similar Chrome and Chromium are.