xserver-xorg-dev - 2:1.20.11-1+deb11u11 main

This package provides development files for the X.Org ('Xorg') X server.
This is not quite the same as the DDK (Driver Development Kit) from the
XFree86 4.x and X.Org 6.7, 6.8 and 6.9 series of servers; it provides
headers and a pkg-config file for drivers using autotools to build
against.
.
Unless you are developing or building a driver, you probably want
xserver-xorg and/or xserver-xorg-core instead.
.
More information about X.Org can be found at:

.
This package is built from the X.org xserver module.