/usr/share/doc/libsane/supported.html is in libsane-common 1.0.22-7ubuntu1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/doc/libsane/html/sane-mfgs.html
/usr/share/doc/libsane/html/sane-mfgs.html