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

<% define_content :link do %>
  <%= course_users_url(asset.course_id) %>
<% end %>

<% define_content :subject do %>
  <%= t :subject, "%{user} accepted the Course Invitation", :user => asset.user.name %>
<% end %>

<%= t "%{user} just accepted their invitation to participate in the course, %{course}. Course role: %{role_type}",
    :user => asset.user.name, :course => asset.course.name, :role_type => asset.readable_role_name %>

<%= t :details, "See the list of current enrollments here:" %>
<%= content :link %>