1040-SR?

All the time I was doing my 2020 tax return with TurboTax, I thought I was using Form 1040. That's what I would look at when switching from EasyStep to Forms. But when I printed a digital copy of my tax return after filing it electronically, I saw that what was submitted was Form 1040-SR. But the strange thing is that when I look at the list of available forms in Form mode, there is a Form 1040 and a Form1040/1040-SR Worksheet, but no Form 1040-SR. Where is Form 1040-SR?