Red cross hatched areas on maps

Noticed this looking at my feeder maps. They all seem to be military installations throughout the world. Is there any significance to these areas on the maps such as MLAT data not being processed/shown if it appears inside the shaded area?

They are military areas but there’s not particular significance in terms of mlat etc; that’s just how openstreetmap (which is the source of the map data/tiles) shows them.

Cool deal. Figured it was from OSM but didn’t find anything with a search on the forums.