Or really meant to be interpreted by them either (or law students).

The rules of the game can be as constricting or permissive as the Imms want them to be, and that's pretty much it.
Arguably Trib both interprets and executes the laws, but does not write the laws as that is the role of IMMs.

Imms = Congress and Supreme Court
Provost = Executive and Appellate Courts
Provincials = Lower executive, district courts.
Magistrates = police

Would be interesting if they had true sep of powers, and made 3 leaders.
Provost is the Congress, makes the laws (in accordance with the Imms)
Vindicator executes the laws and has authority over magistrates
Justiciar interprets the laws

But I don't think Thera needs a robust legal system since it's a game and the Imms can just set the rules and that's the end of it.