/usr/include/claw/tween/easing/ is in libclaw-tween-dev 1.7.3-1+b2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/claw/tween/easing/easing_back.hpp
/usr/include/claw/tween/easing/easing_bounce.hpp
/usr/include/claw/tween/easing/easing_circ.hpp
/usr/include/claw/tween/easing/easing_cubic.hpp
/usr/include/claw/tween/easing/easing_elastic.hpp
/usr/include/claw/tween/easing/easing_expo.hpp
/usr/include/claw/tween/easing/easing_linear.hpp
/usr/include/claw/tween/easing/easing_none.hpp
/usr/include/claw/tween/easing/easing_quad.hpp
/usr/include/claw/tween/easing/easing_quart.hpp
/usr/include/claw/tween/easing/easing_quint.hpp
/usr/include/claw/tween/easing/easing_sine.hpp
/usr/include/claw/tween/easing/impl/
/usr/include/claw/tween/easing/impl/symmetric_easing.tpp
/usr/include/claw/tween/easing/symmetric_easing.hpp