in researching 'zythum' (link) I also ran across 'zyxt' - actually this happened in reverse; I was trying to verify that zyxt was the last word in the OED and discovered it ain't that anymore, and zythum is. Ammon Shea verifies this in his Reading the OED, by saying zyxt "has been stripped of its headword status and moved to the middle of a heap of variant spellings of see", which I can also see from an OED2 entry (online).

what I'm wondering then is, was there really a headword for zyxt in OED2, and it was just dropped? is this typical of what they're doing in the online updates?! and, if so, what's that say about maintaining a history of the language??