mtConfidence attribute namespace clarification

In section 5.9.7.5.4 MT Confidence Annotation

We define an mtConfidence attribute:

"The attribute its:mtConfidence MUST be set and is used to map to and from the
[ITS] defined mtConfidence attribute."

Is it an ITSM attribute or an ITS attribute?
If it's an ITS attribute the part about 'map to and from' is irrelevant (it
doesn't map to its:mtConfidence, it is it).
If it's an ITSM attribute it needs to be itsm:mtConfidence.

The links points to:

[[
5.9.12.19 mtConfidence

Machine Translation Confidence - the mtConfidence attribute exactly corresponds
to the [ITS] defined mtConfidence attribute.
]]

And I'm still confused: there is no indication to which namespace that attribute
belongs: if it's the ITS attribute then it doesn't
'corresponds', it is just it, and then we should just use something like:

[[
Machine Translation Confidence - the its:mtConfidence attribute.
]]

With a link to https://www.w3.org/TR/its20/#mtconfidence-local