Where/how is font scaling decided?

8.17 flatpak

On my system I am using 150% logical scaling which is 144 ppi.

Looking at the example text window in DrRacket the font size value doesn't match other native apps. Since in my previous issue I was having issues with the smoothing, I thought, let's try a bitmap font instead and see what it snaps to.

So, in my terminal I have a bitmap font that snaps into the pixels at size 9. But in the DrRacket example size window I have to set the value to 13 for it to snap into place to match how it appears in the terminal.

You might say, ok, so set it to 13 then. But.. new issue now.. the editor is scaled correctly, but the output pane below is not. The one with the "Welcome to DrRacket, version 8.17 [cs]." line.. it is using a different size or font, because it is shaped poorly instead of matching the editor.. is that set separately elsewhere?

Example below. To see it pixel-perfect on a 150% scaled display you need to open it in a new tab and adjust your browser scaling to 67%.

No source files, tests, or entry points are named. Start by reproducing the report in DrRacket 8.17 Flatpak at 150% logical scaling, comparing the example editor and output pane fonts; done means both panes use consistent, correctly scaled rendering.