In T274031: Provide custom editing interface for GrowthExperiments on-wiki configuration, a new Special:EditGrowthConfig special page will be introduced. In its initial version, the special page will only allow to edit configuration aspects that are not already a part of MediaWiki:NewcomerTasks.json, ie. it only allows to edit variables currently managed by global variables.
Scope of this task
Add an interface for maintaining stuff from MediaWiki:NewcomerTasks.json directly from Special:EditGrowthConfig.