Mystery Yarn

I have a mystery yarn.  Not a mystery yarn as in ‘I lost or threw away the tag, sure in the knowledge that I would remember the info’ (note to self, you will not remember).  No, a different sort of mystery.  I totally have the tag.  But the tag does not seem to match up with any of the listings I can find online.

The brand is the Great Adirondack Yarn Company.  Them I can find.  It’s the base that’s tricky.  The tag lists it as “ROSA 3/5.”  It also says that it’s 100% merino superwash, that it’s 232 yards long, and that the colorway is mixed berries (number 1110).  You’d think that would be plenty of info, but somehow I can’t seem to find any mention of Rosa or Rosa 3/5.  Not on Adirondack’s page, nor on ravelry’s.

Anybody have any insight?  Because I’m playing with a lovely skein of this stuff, and I want to give credit where credit is due when I list it.