ZeroK-RTS
Radar icons: Djinn and Conch work while wet
Amphs have two chassis backgrounds for their radar icons: a circular dome for units that float to the surface, and a trapezoid for those that work while wet (right now all amph units belong to exactly one of the two).
Djinn, and Conch with the "show chassis on cons" option, have the dome chassis background even though they both work while wet and can't float.
Hm, has anyone complained? I recall the theory being about being able to deal damage from underwater.
It spent a month in my todo list to verify whether there is any sort of consistent rule so I don't remember anymore how I picked this up. I also remembered the rule (in the form of "has torpedos" because it's pre-Limpet) but Lobster has the wet icon as well and it's a support unit.
Anyway, it's a minor thing and not necessarily worth the confusion. Perhaps the ideal, if doing anything at all, would be only apply this to new installs.