>>2895516Every work on pixiv is original by your definition, since it's not a reposting site. But other works of Yui aren't tagged as original. It seems obvious it refers to OC on pixiv.
And as I said, I think it's tagged that way on danbooru because of the fig in the background. I admit my interpretation of the tag is a stretch, but if you look on the other works with that tag, I don't see a trend of characters being drawn as older, so it doesn't add up with your interpretation.
