/usr/lib/x86_64-linux-gnu/pkgconfig/cunit.pc is in libcunit1-dev 2.1-3-dfsg-2.
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=${prefix}
libdir=${prefix}/lib/x86_64-linux-gnu
includedir=${prefix}/include
Name: CUnit
Description: C Unit Testing Framework
Version: 2.1-3
Libs: -L${libdir} -lcunit
Cflags: -I${includedir}
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