I believe this might be the project you're talking about: https://flyweb.github.io/ https://flyweb.github.io/ https://hacks.mozilla.org/2016/09/flyweb-pure-we

I believe this might be the project you're talking about: https://flyweb.github.io/ https://flyweb.github.io/ https://hacks.mozilla.org/2016/09/flyweb-pure-web-cross-device-interaction/ https://hacks.mozilla.org/2016/09/flyweb-pure-web-cross-devi... Unfortunately, I'm a little wary of trusting mozilla to support their groundbreaking/interesting-to-developer projects anymore (for better or for worse, many people applaud their renewed focus on Firefox)