Binary package “xserver-xorg-core-dbg” in ubuntu trusty

Xorg - the X.Org X server (debugging symbols)

 The Xorg X server is an X server for several architectures and operating
 systems, which is derived from the XFree86 4.x series of X servers.
 .
 The Xorg server supports most modern graphics hardware from most vendors,
 and supersedes all XFree86 X servers.
 .
 This package provides debugging symbols for the Xorg X server and associated
 modules.