I've found a janky workaround using ForceBindIP.
.\ForceBindIP64.exe 192.168.128.1 .\LibreWolf\librewolf.exe -profile Profiles\Default
This bypasses Librewolf Portable entirely, launching the browser executable itself and manually specifying the profile path so that we don't leave a trace in the AppData folder and actually make the data "portable".
For this to actually work, you have to go in about:config
and set browser.launcherProcess.enabled
to false
so that ForceBindIP actually binds.
Support for this could definitely be implemented within the Portable launcher, but I'm not putting my hopes up.
so that’s what all the buzz is about