uMatrix/dist/firefox/updates.template.json

{
 "addons": {
  "uMatrix@raymondhill.net": {
   "updates": [
    {
     "version": "$ext_version",
     "browser_specific_settings": { "gecko": { "strict_min_version": "56" } },
     "update_info_url": "https://github.com/gorhill/uMatrix/releases/tag/$tag_version",
     "update_link": "https://github.com/gorhill/uMatrix/releases/download/$tag_version/uMatrix_$tag_version.firefox.signed.xpi"
    }
   ]
  }
 }
}