It was somewhere outside Barstow when "SonomaProducts.com"
wrote:

I've found mortising for chairs to be near the height
of woodworking challenges

I certainly don't like rounded-end tenons on chairframes. They're
plenty strong when glued, but they lose rigidity (and also strength, I
suspect) when the glue inevitably fails with age. Quality furniture
has a long tradition of outlasting its glued joints, with the aid of
appropriate joinery.