redmine/app/views/common/_file.html.erb

<div class="autoscroll">
<table class="filecontent syntaxhl">
<tbody>
<% line_num = 1 %>
<% syntax_highlight_lines(filename, Redmine::CodesetUtil.to_utf8_by_setting(content)).each do |line| %>
  <tr id="L<%= line_num %>">
    <th class="line-num"><a href="#L<%= line_num %>" data-txt="<%= line_num %>"></a></th>
    <td class="line-code">
      <% if line == "\n" or line == "\r\n" %>
      <br>
      <% else %>
      <div><%= line.html_safe %></div>
      <% end %>
    </td>
  </tr>
  <% line_num += 1 %>
<% end %>
</tbody>
</table>
</div>