It's mostly done for USPS only. I don't have time these days to continue development, so if someone wants to pick this up - that would be great.
My code is available @ https://github.com/istepura/zeroclickinf...
(branch packtrack) .
There are couple of points, worth mentioning
1) USPS, FedEx, UPS provide tracking information in XML only. AFAIK XML is not welcomed in spice handlers
2) To get access to FedEx and UPS API one have to have an enterprise account (I guess, DDG can help with that)
3) Tracking plugins differ mostly in server part (different API URLs, Tracking # formats) and client JS is mostly the same. I moved common (rendering) JS functionality into separate files, so that provider-specific code need only to prepared data for rendering. Another approach could be running sort of XML-to-JSON proxy on DDG side, which would redirect calls to various tracking API, handle XML response, and return uniform JSON result to JS, so that client side JS would be siply rendering the response.
Sorry for the lack of updates, good luck