Your observation is sharp, but it's not just metainfo—it's load-bearing text. To remove it, you need to delve deep and alter the tapestry of carefully selected words.
edit: almost forgot the "—"
s/text/prose/ s/'/’/
The honest seam is obvious: claudish works; imitation does not. That’s not nothing.
very difficult to remove text watermarking
There must be some set of outputs that is completely resistant to watermarking. For example if I told Claude to output "Hello, World"
Outputs can be easily translated from the watermarked language to another, either by just knowing two+ languages, or via non-LLM translation.