PyYAML is used to produce the canonical form.
When I read the specification:
"Canonical Form ... is a Unicode character string ..."

I think you are right and it should be "Über" instead of "\xDCber".

I think it is better to contact PyYAML developers to ask for clarification.

http://pyyaml.org/report/1

Andrey





It looks nice!

One concern that I have is how the service perceives "Canonical
content" when handling characters above 128. For example:

English: Over
German: Über

Becomes:

%YAML 1.1
---
!!map {
    ? !!str "English"
    : !!str "Over",
    ? !!str "German"
    : !!str "\xDCber",
}
...

Yes, it's a different way of presenting the same thing. But if I was
pressing the "Show Canonical YAML" button, I would expect:

%YAML 1.1
---
!!map {
    ? !!str "English"
    : !!str "Over",
    ? !!str "German"
    : !!str "Über",
}
...

Best regards,

Peter