There is a warning messeage in Version 3.0.2 of KG and MW 1.43
Warning
: Undefined global variable $wgKnowledgeGraphColorPalettes in
extensions/KnowledgeGraph/includes/specials/SpecialKnowledgeGraphDesigner.php
on line
65
Warning
: Trying to access array offset on null in
extensions/KnowledgeGraph/includes/specials/SpecialKnowledgeGraphDesigner.php
on line
65
Easy fix is to add the definition of $wgKnowledgeGraphColorPalettes in LocalSettings.php, but this should not be necessary.