Where is this sheat from?

[A. G. Maisey]

Detlef, I cannot answer this question with any claim to certainty, I'll leave that to somebody else with more knowledge in this specific field --- rather suspect it would be incorrect, but I do not know the acceptable variations.

However, here are some images of a blade that has suffered the same, or similar, damage as has yours, and the repair that was carried out in the place of origin.