The Bog Loop is new. It's owned by Milwaukee County Parks and maintained by Metro MTB. I made a trace of the path by cycling around it 4 times with a good GPS. Here's and article about it...

https://www.jsonline.com/story/communities/north/2024/06/18/new-mountain-bike-trail-opens-at-kletzsch-park-in-glendale/74135461007/