Printing to PDF uses different styles which makes PDF's more book-like. The styles we currently use (or the mechanism itself) for example do not include table backgrounds. In general, this is a good approach but sometimes the cell background color has a meaning and it should be included in the PDF file.

Steps to reproduce:
a) Go to PHP Article on English Wikipedia. Scroll down to Release History section. You'll find that the table uses red/green/yellow/blue background color to present information about the release: old release|stable release|future release etc.
b) Click Download as PDF or Print buttons (the same behavior happens when we print using chromium - T176627 ) and inspect the output. The releases table is there but without colors which makes readers confused as the labels says "red - old release, yellow - stable release, etc..." but everything is black and white.