Yep, this is valid HTML according to the spec, and should have no affect on accessibility. It might not be “valid” according to the W3C validators, but neither

Yep, this is valid HTML according to the spec, and should have no affect on accessibility. It might not be “valid” according to the W3C validators, but neither are many perfectly normal practices like proper custom elements (hyphen in tag name) and wrapping links around container elements. The era where validators were worth following has passed — we're now in the era where you need to learn to look at the spec for the laws of the land. For a beginner React tutorial, I’m happy to see the React parts given emphasis, and the other parts don’t matter simplified. Omitting those tags reduces noise, and is a good subtle way for people to discover that they are in fact optional.