Those moving skeletons between Blender and Unreal (or other DCCs & game engines) will be happy about this visualization option for Relationship Lines. Thx @sybren for the help with this.
More details here on rigging features in the June 27th release of Blender 3.6 LTS. https://wiki.blender.org/wiki/Reference/Release_Notes/3.6/Animation_Rigging
Reference/Release Notes/3.6/Animation Rigging - Blender Developer Wiki