I did start playing around with this locally, but there are a few hurdles to overcome, not least of which is I need to pay for an apple developer account in order to be able to distribute the extension 
I also had some issues with the download api not being available, but I found a workaround for that, and I was having some issues with the context menu options not quite working, which I need to have another look at.
I want to make it work, but having to fork out AUD$149 (per year) just to supply a completely free extension I make for fun in my spare time seems a bit steep to me, and is a big roadblock.