[MM3-users] Templates via Webinterface are i) not set, and ii) set templates (files) are not shown in the Webinterface

I use mailman3 since a while, for some of my lists I have been using

• list:member:digest:footer.txt
• list:member:regular:footer.txt

When I go to "Vorlagen" (LC: DE) (templates) in the web interface, I do _not_ see these two templates!

When I got o my newest mailing list and when I setup templates via the Webinterfaces, these are shown there, but are neither working nor seen as files.

What's wrong here? Is that a problem of the localisation language (DE)? Bug, feature or misunderstanding of myself?