in reply to Documentation on special outside links?
Well, you're right. This has been discussed previously. Other random points:
[jargon://] points to the University of Amsterdam is because, at the time, I was working for a place using a web filter that blocked tuxedo.org as a "hacker" site. It was therefore not available to me--or anyone else who (for whatever reason) was using that web filter. (BTW, it's common to find such filters in place through business connections).
The University's site was available through the filter, had been recently updated with the "official" version of the Jargon File, was reasonably responsive, and also contains some other interesting reference material--in English.1
The reason there's no [e2://] tag is simple. No one's suggested it before; at least not AFAIK. I'll add it to the list of potentials (along with [dict://], [imdb://], and a couple of others that've been /msg'd to me.)
The nice, complete list of prefix tags (as I call them) is available at What shortcuts can I use for linking to other information?
1 - Of course, the nearby presence of at least two monks of my acquaintance had nothing to do with it.