Firefox 52. Winner for actually browsing the web on XP: Mypal.
After Firefox 57 (dubbed "Quantum"), Mozilla killed XUL extensions, forcing everything to use WebExtensions API. While WebExtensions are more secure, they lack deep system-level access. portable firefox 52
: It supports "Classic" add-ons (XUL-based) that were discontinued in Firefox 57. Setup and Usage Firefox 52
The primary reason many enterprises and power users clung to Firefox 52 was its support for . Mozilla killed XUL extensions