Could we add two new constants to the // Realms section of uo.em. This would at least give newcomers some reference point for those two facets (realms).

This is a poor compromise to what I was going to suggest. My original wish was to change the actual constants for those realms to their proper names but I knew that would wreak havoc for existing servers, not that things haven't been changed or done in some way that wreaked havoc before. So I decided on just asking for constants that have the equivalency to the POL names for those realms.

I would like to know the thinking for choosing the names britannia and britannia_alt for the two facets as they were called "Felucca" and "Trammel" when they were introduced by Origin Systems Inc. in Ultima Online: Renaissance but I suppose those developers are long gone.

Up for Yuki

(anyway I'm stuck in ooold pol core version )

I assume you're referring to realm references for core functions?
What about the alternative of adding both names pointing to the same realm number?

Yes. That's why I specified the comment line // Realms. in uo.em They don't point to the same realm though and why not use the string constants?

I suppose you could rephrase the declaration as: It accomplished the same purpose. I don't care how you phrase the declaration. The important point is having a constant REALM_FELUCCA and REALM_TRAMMEL that are assigned the string equivalents of POL's nomenclature for map0 and map1.

One question. What did you mean by 'realm number'? The realms are declared as strings. Am I missing something?