/usr/share/mercurial/templates/paper/filelogentry.tmpl is in mercurial-common 4.5.3-1ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 | <tr>
<td class="age">{date|rfc822date}</td>
<td class="author">{author|person}</td>
<td class="description">
<a href="{url|urlescape}rev/{node|short}{sessionvars%urlparameter}">{desc|strip|firstline|escape|nonempty}</a>
{alltags}{rename%filelogrename}
</td>
</tr>
{if(patch, '<tr><td colspan="3">{diff}</td></tr>')}
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