/usr/share/man/man3/XCompositeRedirectSubwindows.3.gz is in libxcomposite-dev 1:0.4.4-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/man/man3/Xcomposite.3.gz
/usr/share/man/man3/Xcomposite.3.gz