These strings are normally used when creating a custom administrator Menu and using modern.xml to populate the Menu.
At this stage the whole functionality is totally broken in 4.0.
It is likely that modern.xml will anyway be modified to fit the new admin menu system.

BTW: I have no idea how you managed to show these as untranslated by using debug lang as the functionality is dead fish.
Install and see left hand menus in extensions.
Which precise page is that? post url please.

@infograf768
I had installed the alpha build somewhere in Dec. Till yesterday, I was doing nightly build update. Even after update the menus where present and untranslated.
Yesterday I installed from fresh build the menu has disappeared.

But untranslated strings are still present. When I go in different menus, the untranslated strings appear.
I feel that, I should test this little later when J4 becomes stable enough.

But untranslated strings are still present. When I go in different menus, the untranslated strings appear.

We may have still untranslated strings in general, but do you still get these in debug lang is the question.

Yes, I see the untranslated strings but not in the left hand menu.

I am asking you on which page? URL ?

I mean for the strings you quote originally.

No, they are not.

Let's close this then and see what happens when custom admin menus creation is corrected.