Date: 2026mar25 OS: Android Q. Firefox: Setup development of extensions for Firefox for Android on Ubuntu in VirtualBox A. On Virtual Box: Update to latest version and install extensions Let your phone's USB device thru to guest VM On Ubuntu: apt install npm npm install --global web-ext apt install android-sdk On phone: Enabled developer mode Enable USB debugging when asked Turn on USB debugging in Firefox Then follow instructions on the official site: https://extensionworkshop.com/documentation/develop/developing-extensions-for-firefox-for-android/