As you know, most countries in OGF have maritime boundaries, but they are not consistent with tagging. There are typically 4 variants:
admin_level=2(like regular boundaries)
border_type=territorial(I personally used this one)
However, according to OSM standards, I propose that we all start to use this one:
This will be very useful for consistency, and it also prevents the maritime boundaries from rendering at low zoom levels (which makes the map clearer and better-looking).