The Navy SEAL was an infantry unit cut from Generals.
Essentially being the USA's analogous equivalent to the Red Alert 2 SEAL, American SEALs would have likely performed the same role as Burton does in the final game; a skirmish unit excelling at anti-infantry and base sabotage.
However, much of the SEALs supposed roles overlap with other infantry units; anti-infantry by the Pathfinder and base sabotage by Burton. Therefore the SEAL was removed before it could be coded into the game.
Only the incomplete model and an unused cameo remains within the game files.