It's a product of Canada, and soooo much better than the other stuff we've had in the past. They have one that's "old style" with whole mustard seed, and another that's dijon (yellow creamy style).
I haven’t found one yet. I am all ears. Most that I have seen mentioned by people I can’t find in store. There are some local small producers but often the mustards are flavoured. So far I stick with German brands.
I don't know the answer, but I was struck with a moment of appreciation for the fact that at least you don't need to specify "vegan mustard" in the question. Thank fruc that non-vomit mustard is pretty much always vegan.
https://madeincanadadirectory.ca/cat/canadian-mustard/
I like Kozlik's but you do you.