From OpenStreetMap Wiki
|Problematic tag, see wiki.|
|Used on these elements|
|Tools for this tag|
|This key page is a stub. You can help OpenStreetMap by expanding it.
Similar pages for structural reference: Key:religion, Key:waterway.
Do not use sub_sea=stream, it is an artefact from an import and needs to be cleaned up. Of the total taginfo count almost 5000 are from this import.
Taginfo for sub_sea=* is misleading because it counts the above mentioned artefacts.