Subject: bug#48528: Extension firefox purevpn doesn't run on icecat

From: bbb ee <[email-masked]>
Date: Wed, 19 May 2021 22:27:00 +0000

## Reproduce the bug
install purevpn from
https://addons.mozilla.org/en-US/firefox/addon/purevpn-for-privacy-security/

in the tool bar,
1. click on the icon of purevpn
2. click "Select Country"
It should display a list of country, but any thing is display.

## Version
icecat version: GNU IceCat 78.8.0esr
purevpn version : Version 3.11.0