It would be very useful to be able to send structured data, including Blobs, through the BroadcastChannel API.
This is something we've seen any time we've done storage or message passing, that one of the first thing authors ask for is to not have to do JSON serialization/parsing manually. The ability to pass ArrayBuffers and Blobs is somewhat less commonly asked for, likely because binary data is less often used, but seems important nonetheless. We can't allow transferring of objects, since you can't transfer something to all listeners of a broadcasting API. But plain structured clones should be no problem to support conceptually (though more work to implement of course). We've started looking at doing structured clone support for Firefox and likely won't ship until we have that implemented. / Jonas