Headers are indentical

app/views/notifications/_notification.html.erb

@@ -2,7 +2,7 @@
   <%= notification_tag notification do %>
 
     <header class="card__header">
-      <%= render "notifications/notification/#{notification.source_type.underscore}/header", notification: notification %>
+      <%= render "notifications/notification/header", notification: notification %>
     </header>
 
     <div class="card__body">

app/views/notifications/notification/mention/_header.html.erb

@@ -1,22 +0,0 @@
-<div class="card__board">
-  <span class="card__id">
-    <span class="for-screen-reader">Card number</span>
-    <%= notification.card.id %>
-  </span>
-  <span class="card__board-name">
-    <span class="overflow-ellipsis"><%= notification.card.board.name %></span>
-  </span>
-</div>
-
-<div class="card__notification-meta overflow-ellipsis flex-item-grow flex-item-no-shrink flex-item-justify-end">
-  <span class="card__creator"><%= notification.creator.familiar_name %></span>
-</div>
-
-<div class="card__notification-meta overflow-ellipsis flex-item-no-shrink">
-  <span class="card__timestamp"><%= local_datetime_tag(notification.created_at, style: :timeordate) %></span>
-</div>
-
-<div class="card__notification-meta flex-item-no-shrink">
-  <%= notification_toggle_read_button(notification) %>
-</div>
-