/usr/lib/x86_64-linux-gnu/pkgconfig/jdns.pc is in libjdns-dev 2.0.3-1build1.
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=${prefix}
libdir=/usr/lib/x86_64-linux-gnu
includedir=/usr/include/jdns
Name: jdns
Description: Simple DNS implementation can perform normal DNS queries
Version: 2.0.3
Libs: -L${libdir} -ljdns
Cflags: -I${includedir}
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