Ok, it's on the SVN now.
Just to clarify, Troops and People are defined as Special Unit Types and many land units have one or the other defined. Many transport units, usually those that can transport troops, actually don't have either one specified as the type they carry but rather rely on a domain definition to define what they can carry and can thus transport both types.
However, there are also ships that define only People are what may be transported. Caravels and Subs, for example, can only transport People. For those, it's important to make the distinction, because Troops and People both mean different base transport volume when on Size Matters, as there is no difference between type there for what specialunittypes are transportable, and not on SM, you don't have these definitions on transports so much as how they apply to the volume of what the promotions add. The ability to commit the transport unit from a ship configured (with weapons and cargo holdings) from people to troops was something I wanted to enable.
However, I also wanted to enable units that weren't transports of any kind to be able to promote itself to transporting people types.
Anyhow, it's extremely complex, particularly when you factor in that now captives are a 'type' and so are missiles and HVAC hovering take off and landing vehicles. This is a large part of what should be swappable by these type changes. The configuration switch from a sub holding missiles to holding people or vice versa, for example, is an example. A Cruiser type should be able to swap from carrying missiles to carrying people or seaplanes or HVAC, but not All Air types, thus not fighters and bombers.
Again, complicated and hard to explain. You've given me cause to realize how I needed to adjust the People transport option, which exists for units that don't have a transport designation or for units that have a designation of people, missiles, or other types, except for Carrier ships.
Yes, DH and I came to the conclusion that the best answer to all of this is to make it possible for the code to accept that ships can have multiple type transport designations. So that's another future project to go back in and adjust everything to allowing. A very very big project. The only reason I did as much as I have here is because SM demanded it be done and a few simple (or so it seemed) concepts emerged along the way there. And it's still not bug clean. Something is very wrong somewhere, like I have not figured out where all units can become loaded or unloaded. I suspect it's in python that's causing unit counts to go off somehow.