/usr/share/gtk-doc/html/poppler is in libpoppler-glib-dev 0.18.4-1ubuntu3.2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/gtk-doc/html/../../doc/libpoppler-glib-dev/html/poppler
/usr/share/gtk-doc/html/../../doc/libpoppler-glib-dev/html/poppler