Mypal68 style portable mode

[K4sum1]

The portable mode in Mypal68 is that you just put a blank file named pmprt.mod into (browser executable folder)\browser, and without any external executables, launch commands, or anything, the browser is just fully portable.

I just ported this to my fork of Firefox which is based off of 125. The code should just be able to be dropped in since I only had to barely modify it to get it from 68 to 125.

Eclipse-Community/r3dfox@1369465

[MrAlex94]

Thanks for this! Looks interesting (and sorry for the late reply). I'll do some testing on this, as I've had issues in the past messing around with profiles.