canvas-lms/app/messages/account_notification.email.erb

<% define_content :link do %>
  <%= dashboard_url %>
<% end %>

<% define_content :subject do %>
  <%= before_label asset.subject %> <%= asset.account.name %>
<% end %>

<%= html_to_text(asset.message, :base_url => dashboard_url) %>

<%= content :link %>