$wgBabelCategoryNames currently isn't set for nds.wp, which results in users not being categorized by their proficiency level when setting the Babel boxes. We'd like to change this behavior, see: https://nds.wikipedia.org/wiki/Wikipedia_Diskuschoon:Babel#Wat_de_Babel-Textbostenen_vertellt
So could you please change InitialiseSettings.php and add the following lines to the wmgBabelCategoryNames section? Thank you!
'ndswiki' => [
'0' => false, '1' => 'User %code%-1', '2' => 'User %code%-2', '3' => 'User %code%-3', '4' => 'User %code%-4', '5' => 'User %code%-5', 'N' => 'User %code%-M',
],