/usr/include/xqilla/operators/ is in libxqilla-dev 2.3.0-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/xqilla/operators/And.hpp
/usr/include/xqilla/operators/ArithmeticOperator.hpp
/usr/include/xqilla/operators/ComparisonOperator.hpp
/usr/include/xqilla/operators/Divide.hpp
/usr/include/xqilla/operators/Equals.hpp
/usr/include/xqilla/operators/Except.hpp
/usr/include/xqilla/operators/GeneralComp.hpp
/usr/include/xqilla/operators/GreaterThan.hpp
/usr/include/xqilla/operators/GreaterThanEqual.hpp
/usr/include/xqilla/operators/IntegerDivide.hpp
/usr/include/xqilla/operators/Intersect.hpp
/usr/include/xqilla/operators/LessThan.hpp
/usr/include/xqilla/operators/LessThanEqual.hpp
/usr/include/xqilla/operators/Minus.hpp
/usr/include/xqilla/operators/Mod.hpp
/usr/include/xqilla/operators/Multiply.hpp
/usr/include/xqilla/operators/NodeComparison.hpp
/usr/include/xqilla/operators/NotEquals.hpp
/usr/include/xqilla/operators/Or.hpp
/usr/include/xqilla/operators/OrderComparison.hpp
/usr/include/xqilla/operators/Plus.hpp
/usr/include/xqilla/operators/UnaryMinus.hpp
/usr/include/xqilla/operators/Union.hpp