Standardization would be a useful outcome, having multiple implementations shipping is a prerequisite as I understand it - it's something Mozilla could particip

Standardization would be a useful outcome, having multiple implementations shipping is a prerequisite as I understand it - it's something Mozilla could participate in, along with other interested browser vendors. There's a community group: https://www.w3.org/community/browserext/ https://www.w3.org/community/browserext/ but no WG yet as far as I can tell.