/usr/share/doc/libvorbis-dev/html/vorbisenc/ is in libvorbis-dev 1.3.5-4+deb9u2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/doc/libvorbis-dev/html/vorbisenc/changes.html
/usr/share/doc/libvorbis-dev/html/vorbisenc/examples.html
/usr/share/doc/libvorbis-dev/html/vorbisenc/index.html
/usr/share/doc/libvorbis-dev/html/vorbisenc/ovectl_ratemanage2_arg.html
/usr/share/doc/libvorbis-dev/html/vorbisenc/ovectl_ratemanage_arg.html
/usr/share/doc/libvorbis-dev/html/vorbisenc/overview.html
/usr/share/doc/libvorbis-dev/html/vorbisenc/reference.html
/usr/share/doc/libvorbis-dev/html/vorbisenc/style.css
/usr/share/doc/libvorbis-dev/html/vorbisenc/vorbis_encode_ctl.html
/usr/share/doc/libvorbis-dev/html/vorbisenc/vorbis_encode_init.html
/usr/share/doc/libvorbis-dev/html/vorbisenc/vorbis_encode_init_vbr.html
/usr/share/doc/libvorbis-dev/html/vorbisenc/vorbis_encode_setup_init.html
/usr/share/doc/libvorbis-dev/html/vorbisenc/vorbis_encode_setup_managed.html
/usr/share/doc/libvorbis-dev/html/vorbisenc/vorbis_encode_setup_vbr.html