Hi,
I wonder why does this feature not render in any form on OSM at all?
https://wiki.openstreetmap.org/wiki/Tag:man_made%3Dreservoir_covered
It’s a perfectly legit feature with a water droplet icon in iD Editor, so why does this icon not appear on OSM?
note that there are many map style and you may think specifically about OpenStreetMap Carto - OpenStreetMap Wiki - it renders many features (about 400), but not all of them due to various limitations
request to render it is tracked in Render man_made=reservoir_covered areas · Issue #2620 · gravitystorm/openstreetmap-carto · GitHub