Apple Mail - iCloud automatically making a new folder labeled ... " ...

First of all I would like to know what kind of Apple Mail iCloud sub-folder is automatically being made in my Apple Mail .... with the folder label of ... " ... (see attached reference image)?

I once deleted this iCloud Mail folder, but Apple iCloud Mail keeps automatically replacing it.

Notice in the attached image, that the folder is also not "tinted darker" like the other default

iCloud mail folders!

Has anyone experienced this in their Apple iCloud Mail Folder ... or have any suggestions as to what is going on here and how to, fix it