I'm running a browser extension (or should I say "add on"?) which requires the presence of a so called "companion app".
In a non-portable environment such an app has to be installed in the main OS, as well as the browser itself.
I'm wondering whether there is a way to "install" such an app inside the FF Portable's folder, in order to carry it around together with the browser, in a USB key or similar device.
PS. I searched, before posting, for similar questions but did not find any.
That would more be a question for the publisher. These types of things generally rely on a registry key set to point to the correct path, usually in HKLM which would require admin rights. You could try installing the app to a virtual machine and doing a regshot before and after capturing both the registry and the full C: drive to check what it might be looking for. Or dive into the extensions JS code to see how it does it.
Sometimes, the impossible can become possible, if you're awesome!