/usr/lib/pkgconfig/libcryptsetup.pc is in libcryptsetup-dev 2:1.6.1-1ubuntu1.
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 | prefix=/usr
exec_prefix=${prefix}
libdir=/lib
includedir=${prefix}/include
Name: cryptsetup
Description: cryptsetup library
Version: 1.6.1
Cflags: -I${includedir}
Libs: -L${libdir} -lcryptsetup
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