Is there any way I can host a JS file in {domain}/file.js?

[bobthebear]

linking to a related topic:

Meta Tags and Root Dir Files?

insert shocked Pickachu face here that'd be awesome if we could get a three way call or email like that to understand what's going on and what it means for us as far as js goes and what limitations there might be by design. If Google Adsense support is added, it makes my questions right now a bit pointless, but I think the answer could be helpful in providing others with temporary solutions for any other metatag based services and/or standards found lying around interwebs