La Forge:
New Moon (temp. name) a.k.a. Pale Moon fork targetting XP FAQ:
Q: Having audio distorted when watching Twitter/etc.?
A: Please try turning on "Firefox compatibility" in options dialog or either "general.useragent.compatMode = 2" or "general.useragent.compatMode.firefox = true" in about:config and reload the page.
Q: Can't play H264 clips? (for PM27/KM76)
A: Download following packages for your browser edition(32bit/64bit) and extract DLLs to same place as palemoon.exe lives.
32bit LAV dlls are in separated package (extracted from K-Lite codec pack 13.5.5)
https://o.rths.cf/palemoon/lav.7z
Just in case if you have an older processor which has no SSE instruction set support:
32bit NoSSE (ffmpeg 3.1.1 lite build)
https://o.rths.cf/palemoon/lav-dll-lite-mmx.7z
32bit No ASM (ffmpeg 3.1.1 lite build, if build above doesn't work on your processor)
https://o.rths.cf/palemoon/lav-dll-lite-noasm.7z
64bit LAV dlls are in separated package (LAV Filters 64bit 0.70.2)
https://o.rths.cf/palemoon/lav64.7z
Q: AV1 Support? (for UXP-based applications except mailnews)
A: You need to enable "media.av1.enabled" in about:config
Q: VP9 Support? (for PM27)
A: VP9 works if async MSE option is unchecked and "Enable MSE for WebM Video" checked in options.
Q: Extensions/Themes not working after updating binaries.
A: If you encounter extensions not show icon, clicking options button of extension causing browser unresponsive, etc. please try following actions:
1.a Killing palemoon.exe process
1.b Copy whole extensions folder out of profile folder (to somewhere else for example, desktop)
1.c Restart browser without restoring previous sessions
1.d Goto about:addons page
1.e Drop XPI files from the copied-out extensions folder to about:addonss page One-by-One.
1.f After all XPI files are dropped and installed/updated, restart browser