/usr/lib/x86_64-linux-gnu/pkgconfig/xcb-shm.pc is in libxcb-shm0-dev 1.12-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 | prefix=/usr
exec_prefix=${prefix}
libdir=${prefix}/lib/x86_64-linux-gnu
includedir=${prefix}/include
Name: XCB Shm
Description: XCB Shm Extension
Version: 1.12
Requires.private: xcb
Libs: -L${libdir} -lxcb-shm
Cflags: -I${includedir}
|