First, thanks for this gem "PortableApps".
I would like to report a possible Bug at Firefox Nightly Portable 64-bits latest version, in Windows 10 latest version: Add-ons settings and content are not portable.
Installed add-ons may appear at Nightly' "about:addons" page, but add-ons are inaccessible, no settings, no contents.
Even inaccessible at "about:addons", sometimes installed add-ons work. But considering that they are inaccessible and add-ons also don't appear at NavBar, TabBar, Menus etc, it is impossible to use them.
Doing a kind of detective work, I found that if I delete the "extensions.json" file (at profile folder), Nightly at startup rebuilds this file (add-on indexes), and everything works fine, all the add-ons appear, settings, contents, everything is perfect. So I am not an expert, but the bug seems to have connection with "extensions.json" file.
I did lot of tests, always using latest Nightly Portable + updated, always clean install, add-ons installed brand new today etc.
I also tested in different devices.
Hope someone will fix the bug.
Thank you in advance!