This patch adds ability to set up colors and size of background (transparency) checkerboard pattern in viewport and 2d editors. No new backgrounds, only changing colors in existing ones.
This is not the background of the viewport, it is a transparency checkerboard that is turned on only in render mode, when the transparency mode is on. And also in 2D-editors, (image, sequencer, ets)
How it works:
Useful for bright themes:
Same in Krita: