To build, install web-ext
and run
web-ext build
export FIREFOX_SECRETS=`pass firefox.com | tail -n +2`
export AMO_JWT_ISSUER=$(echo "$FIREFOX_SECRETS" | awk -F': ' '/JWT_ISSUER/{print $2}')
export AMO_JWT_SECRET=$(echo "$FIREFOX_SECRETS" | awk -F': ' '/JWT_SECRET/{print $2}')
web-ext sign --api-key=$AMO_JWT_ISSUER --api-secret=$AMO_JWT_SECRET
where the issuer and key are from https://addons.mozilla.org/en-GB/developers/addon/api/key/
You can install the addon from a folder from about:debugging