Everything about "pox leber" as a minced oath, and an earlier source.

[Koen G]

The thing with pox is that it's something uncivilized people say, so we encounter it in this sermon for the priest to condemn it. That's the kind of attestation you can hope for such a mainly spoken phenomenon, not actual active uses.

What this fragment definitely does for us, is provide our earliest, undeniable evidence of not only the sound, but also the spelling "pox" being understood as the animal. This is very clear in Marco's updated transcription.