Merge branch '4.2' of github.com:Ultimaker/Cura into 4.2

plugins/XmlMaterialProfile/XmlMaterialProfile.py

@@ -1186,7 +1186,7 @@ class XmlMaterialProfile(InstanceContainer):
     def __str__(self):
         return "<XmlMaterialProfile '{my_id}' ('{name}') from base file '{base_file}'>".format(my_id = self.getId(), name = self.getName(), base_file = self.getMetaDataEntry("base_file"))
 
-    _metadata_tags_that_have_cura_namespace = ["pva_compatible", "breakaway_compatible"]
+    _metadata_tags_that_have_cura_namespace = {"pva_compatible", "breakaway_compatible"}
 
     # Map XML file setting names to internal names
     __material_settings_setting_map = {