/usr/share/mercurial/help/ is in mercurial-common 4.5.3-1ubuntu2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/mercurial/help/bundlespec.txt
/usr/share/mercurial/help/color.txt
/usr/share/mercurial/help/common.txt
/usr/share/mercurial/help/config.txt
/usr/share/mercurial/help/dates.txt
/usr/share/mercurial/help/diffs.txt
/usr/share/mercurial/help/environment.txt
/usr/share/mercurial/help/extensions.txt
/usr/share/mercurial/help/filesets.txt
/usr/share/mercurial/help/flags.txt
/usr/share/mercurial/help/glossary.txt
/usr/share/mercurial/help/hg-ssh.8.txt
/usr/share/mercurial/help/hg.1.txt
/usr/share/mercurial/help/hgignore.5.txt
/usr/share/mercurial/help/hgignore.txt
/usr/share/mercurial/help/hgrc.5.txt
/usr/share/mercurial/help/hgweb.txt
/usr/share/mercurial/help/internals/
/usr/share/mercurial/help/internals/bundles.txt
/usr/share/mercurial/help/internals/censor.txt
/usr/share/mercurial/help/internals/changegroups.txt
/usr/share/mercurial/help/internals/config.txt
/usr/share/mercurial/help/internals/requirements.txt
/usr/share/mercurial/help/internals/revlogs.txt
/usr/share/mercurial/help/internals/wireprotocol.txt
/usr/share/mercurial/help/merge-tools.txt
/usr/share/mercurial/help/pager.txt
/usr/share/mercurial/help/patterns.txt
/usr/share/mercurial/help/phases.txt
/usr/share/mercurial/help/revisions.txt
/usr/share/mercurial/help/scripting.txt
/usr/share/mercurial/help/subrepos.txt
/usr/share/mercurial/help/templates.txt
/usr/share/mercurial/help/urls.txt