Tilt-shift lenses aren’t particularly common. They’re often limited to things like architectural and cityscape photography. Or, they’re used for product photography to help correct or create a perspective shift. They’re very handy.
Typically, the exact amount of tilt or shift applied is a best guess. You can take measurements, but they’ll only be so reliable. Canon filed patent #2023160385 with the Japan Patent Office to display the exact tilt and shift amounts on the camera itself.