the meaning of the word Hotseat

[Blau&Gruen]

What are the "hotseat settings" in one of the files coming with the demo for?

1) hotseat for battles only (unlikely because of the "pope" remark)
2) hotseat as a feature used by the programmers but not activated in the final product
3) hotseat as an old dev feature that had been kicked out later (remember RTW: upgrade forts to cities)
4) hotseat as a metaphor "hotseat" ( :hmmm: )
5) hotseat as a feature in the final product
6) hotseat as a non-supported feature but eventually activateable by a mod.