In a PDFView, the OS provides a context menu which contains (among other things) "Actual Size" zoom.
This command wrongly displays the page at 1 point = 1 pixel.
Traditionally on MacOS, "Actual Size" displays the page at 1 inch on page = 1 inch on screen, e.g. for a Letter page, 8.5 x 11 inches on the screen. (So the API needs to determine the display's pixel density to calculate the zoom size.)
In Preview 11.0 on Os 27.2, "Actual Size" in the PDFView context menu and in the View menu both zoom to 1 point = 1 pixel.
In Preview on Sequoia, Actual Size in the View menu displays at 1 inch = 1 inch, but the context menu gives 1 pt = 1px. (The latter presumably relying on the built-in context menu from PDFView.)
Note that in Pages.app, Actual View gives the expected 1 inch = 1 inch on screen.