Firefox for windows 7: Modern Firefox based web browser for Windows 7.
https://github.com/e3kskoy7wqk/Firefox-for-windows-7-REWORK
https://github.com/e3kskoy7wqk/Firefox-for-windows-7-REWORK/releases/tag/debug
https://github.com/e3kskoy7wqk/Firefox-for-windows-7-REWORK/releases/expanded_assets/debug

might also work on Windows XP SP3 and Windows Vista.

firefox-117.0a1.en-US.win32がXP SP3で動いたという書き込み
https://msfn.org/board/topic/183464-updated-drivers-for-windows-xp-sp3-and-windows-2003-sp2-x32x64-for-modern-hardware/page/209/#comments