I found in app.overlay that it is configured for uc8179_7inch5_epaper_gdew075t7 screen.
uc8179_7inch5_epaper_gdew075t7: uc8179@0 {
compatible = "gooddisplay,gdew075t7", "ultrachip,uc8179";
I found this Zephyr doc:
https://docs.zephyrproject.org/latest/boards/shields/waveshare_epaper/doc/index.html