x11proto-core-dev 7.0.16-1 (i386 binary) in ubuntu lucid

 This package provides development headers describing the wire protocol
 for the core X11 protocol, and also provides a number of utility headers,
 used to abstract OS-specific functions.
 .
 This package deprecates 'x-dev', a package from the monolithic builds of
 XFree86 and X.Org.
 .
 More information about X.Org can be found at:
 <URL:http://www.X.org>
 <URL:http://xorg.freedesktop.org>
 <URL:http://lists.freedesktop.org/mailman/listinfo/xorg>
 .
 This package is built from the X.org xproto proto module.