== Background
In {T240889} there was a request to create a notification for anonymous editors when a message is left on their talk page.
== Designs
| non-main namespace pages | not logged-in editor page
| {F34689154 width=300} | {F34689156 width=300}
== Acceptance criteria
Add the yellow banner to the following:
[] All non-main namespaces
[] The "You are not logged in" Screen
== Developer notes
* For contributions page, this can be done inside Minerva:
Should be as simple as adding the template variable `{{{html-user-message}}}` to skin.mustache unconditionally and use CSS to hide and show (display: none by default, display: block with ns-special).
* For talk page a MobileFrontend change is needed. Based on whether the message is present in the Minerva HTML we can copy it across.