/usr/include/gecode/ is in libgecode-dev 4.4.0-3.
This file is owned by root:root, with mode 0o755.
There are a lot of files here (682 total). We're only showing the immediate contents of /usr/include/gecode.
/usr/include/gecode
..
/usr/include/gecode/driver/
/usr/include/gecode/driver.hh
/usr/include/gecode/flatzinc/
/usr/include/gecode/flatzinc.hh
/usr/include/gecode/float/
/usr/include/gecode/float.hh
/usr/include/gecode/gist/
/usr/include/gecode/gist.hh
/usr/include/gecode/int/
/usr/include/gecode/int.hh
/usr/include/gecode/iter/
/usr/include/gecode/iter.hh
/usr/include/gecode/kernel/
/usr/include/gecode/kernel.hh
/usr/include/gecode/minimodel/
/usr/include/gecode/minimodel.hh
/usr/include/gecode/search/
/usr/include/gecode/search.hh
/usr/include/gecode/set/
/usr/include/gecode/set.hh
/usr/include/gecode/support/
/usr/include/gecode/support.hh
/usr/include/gecode/third-party/