/usr/include/simgear/ephemeris/ is in libsimgear-dev 3.0.0-6+b2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/simgear/ephemeris/celestialBody.hxx
/usr/include/simgear/ephemeris/ephemeris.hxx
/usr/include/simgear/ephemeris/jupiter.hxx
/usr/include/simgear/ephemeris/mars.hxx
/usr/include/simgear/ephemeris/mercury.hxx
/usr/include/simgear/ephemeris/moonpos.hxx
/usr/include/simgear/ephemeris/neptune.hxx
/usr/include/simgear/ephemeris/pluto.hxx
/usr/include/simgear/ephemeris/saturn.hxx
/usr/include/simgear/ephemeris/star.hxx
/usr/include/simgear/ephemeris/stardata.hxx
/usr/include/simgear/ephemeris/uranus.hxx
/usr/include/simgear/ephemeris/venus.hxx