Not it was not obvious, thanks for mentioning it.
My Kindle Touch does not have that, but ISTR the feature, mentioned as first introduced on the PW2? (And likely backported to the PW1.)
Always difficult tol remember the features I don't actually have to play with.
IIRC it should use a *.asc file in the sdr folder, next to the book -- Amazon will send it with the ebook when downloading from their servers, and X-Ray Creator can probably create one as well.
But by default, they don't exist, and if the ebook file has updated metadata that won't be automatically reflected in the *.asc
That is the way AuthorProfile.profile.${ASIN}.asc works for About the Author, which my Kindle Touch does have.