Man pages matching name x11::windowhierarchy in section 3pm:

X11::WindowHierarchy.3pm.en	debian 10 / libx11-windowhierarchy-perl
X11::WindowHierarchy.3pm.en	debian 11 / libx11-windowhierarchy-perl
X11::WindowHierarchy.3pm.en	debian 12 / libx11-windowhierarchy-perl