/usr/lib/x86_64-linux-gnu/pkgconfig/registry.pc is in libregistry-dev 4.0.0~alpha18.dfsg1-4ubuntu2.
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 12 | prefix=/usr
exec_prefix=${prefix}
libdir=${prefix}/lib/x86_64-linux-gnu
includedir=${prefix}/include/samba-4.0
Name: registry
Description: Windows-style registry library
Requires: talloc
Requires.private: ldb
Version: 0.0.1
Libs: -L${libdir} -lregistry
Cflags: -I${includedir} -DHAVE_IMMEDIATE_STRUCTURES=1
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