I finally tried the "Siggi's" brand of skyr. Although the label insists on calling it yogurt, the ingredients list shows that it contains vegetable rennet and active cultures, and it has the same taste and texture of skyr.is, so I'd say it's also a skyr, despite the confusing labeling.
I'm noticing that I can't really detect the flavorings put in flavored skyr. (Siggi's blueberry wasn't very distinguishable from strawberry skyr.is, for example.) I've solved this problem by adding my own flavoring ingredients. Tonight with supper I had strawberry skyr.is mixed with two heaping teaspoons of lingonberry preserves. Very tasty.