Transmission had a http interface for a long time already. This seems like something quite similar. If you need to install a plugin or app to make it work it's

Transmission had a http interface for a long time already. This seems like something quite similar. If you need to install a plugin or app to make it work it's not 100% "in the browser" imho. https://trac.transmissionbt.com/wiki/WebInterface https://trac.transmissionbt.com/wiki/WebInterface