[Seirdy]

In the experimental Document-Policy HTTP header, "bpp" does seem to signify bytes per pixel.

Document-Policy explainer: https://github.com/wicg/document-policy/blob/main/document-p...

I tried it out on my own site, and through trial-and-error I found that Chromium does in fact treat the "max-bpp" Document-Policy directives as bytes-per-pixel.

I could be wrong; my memory has faded. Please correct me if this is the case.

[bscphil]

I'm not sure what HTTP headers have to do with anything. Using "bpp" to mean bits per pixel is extremely common in image encoding. See e.g. https://en.wikipedia.org/wiki/Color_depth where an uncompressed image is often 24 bpp (8 bits per channel). It's also common to use bitrate (rather than byterate) in audio encoding, see e.g. https://wiki.hydrogenaud.io/index.php?title=Bitrate