Matrix Games Forums

What does it mean when it says you get one SE unit also it may say something like expierience is capped at 100 %

These are elite units that are awarded to the player for exceptional performances. The makers of the game were prohibited by law (in Europe?) from using the 'SS' label for the elite troops so they used SE. Just think of them as SS troops. The best thing is that, if awarded after a scenario, they do not take up a unit slot in the next scenario, they are 'free' in that regard.

You can always rename a unit accordingly, too.
Just select the appropriate unit (anytime during a game) then press the 'Alt' and 'N' keys together. A new name box will then pop up on the screen.
This works for all units in the game.