redmine/app/views/mailer/message_posted.text.erb

<%= @message_url %>
<%= @message.author %>

<%= @message.content %>

<% if @message.attachments.any? -%>
---<%= l(:label_attachment_plural).ljust(37, '-') %>
<% @message.attachments.each do |attachment| -%>
<%= attachment.filename %> (<%= number_to_human_size(attachment.filesize) %>)
<% end -%>
<% end -%>