/usr/include/freefem++/WHERE_LIBRARY-download is in libfreefem++-dev 3.47+dfsg1-2build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 | error not directory /usr/lib/ff++/3.47/lib and /usr/lib/ff++/3.47/include /build/freefem++-gHfp5w/freefem++-3.47+dfsg1
|