Linguist's Geek Code

Referenced from:

At least 80 signature codes

The Linguist’s Geek Code is presumably for fans of lingustics or learning languages, but aside from a mention on At least 80 signature codes I cannot find any other material about this code.

There is a mention of “geek code” on a post in europa.linguas discussing the value of language codes in signatures, but the conversation did not arrive at a specification that gained any visible use.