/usr/share/doc/libhealpix-java/api/healpix/essentials/ is in libhealpix-java-doc 3.31-2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/doc/libhealpix-java/api/healpix/essentials/Compressor.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/Constants.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/FastMath.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/FitsUtil.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/Fxyf.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/HealpixBase.Xyf.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/HealpixBase.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/HealpixMapDouble.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/HealpixMapFloat.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/HealpixProc.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/HealpixTables.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/HealpixUtils.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/Moc.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/MocFitsIO.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/MocQuery.MocQueryComponent.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/MocQuery.MocQueryOp.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/MocQuery.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/MocStringIO.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/Pointing.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/RangeSet.ValueIterator.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/RangeSet.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/Scheme.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/Vec3.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/Zphi.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/package-frame.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/package-summary.html
/usr/share/doc/libhealpix-java/api/healpix/essentials/package-tree.html