The XML tags are similar to <antml:xxx>, which is obviously Anthropic ML (or ANTrophic xML).

I think it’s likely 3; meta in reverse. While tokenisers and preprocessing can catch it, you want your special tokens to be unique and not present in the original corpus. <meta: is likely too common.

Likely inverted "meta" to avoid collision with HTMLs meta tags

> atem

also perhaps taking some small joy from the lexical similarity to aten[0] namespace that lies at the heart of pytorch

[0]: https://github.com/pytorch/pytorch/blob/main/aten/src/README...

atem also means breath in German