xserver-xorg-dev 2:21.1.7-3ubuntu2 (armhf binary) in ubuntu mantic

 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:
 <URL:https://www.x.org>
 .
 This package is built from the X.org xserver module.