Navigation entry is missing required field `app`

[susnux]

The navigation entry registration is missing the required app field (required since NC28):

external/lib/AppInfo/Application.php

Line 76 in d9de3e5

return [

There should be 'app' => 'external'.

[provokateurin]

I wonder if this was done on purpose for some reason, @nickvergessen do you maybe remember?
I haven't yet seen that this causes any problems.

[nickvergessen]

app field was not required/existing back then.
Compared to the remaining 7yo code, the 10 months is the difference:
https://github.com/nextcloud/server/blame/0a7fcde9069ff05cffe22e2ad6831d866103d12c/lib/private/NavigationManager.php#L377-L378