I do not know what all of them do, but I do know some of them.
Don't eat and no rats: During the daily update, the ship crew will not consume food rations and rats will not consume any ship cargo
Quest Log Show: If this is turned on, during some of the quest actions, a message will show information upper right screen
Test Ransack Captain: Some sort of testing option for enemy captains used in boarding and spyglass, but I'm not sure what it does, but it's probably for script debugging purposes.
Locator Show: If turned on, any model locators will show as bright spheres for the radius of the defined locator and they show as different colors depending on locator type
Exp Log Show: Whenever experience is gained for something, a log message in the upper right screen will display the experience value gained.
P.G.G. Log Show: Sometimes shows messages upper right when the other wandering "heroes" stay in the tavern, change ships, are respawned, tasks, targets, etc. for script debugging purposes.
Camera enable free: There is a free camera mode where certain controls will allow the camera to roam away from the character, but I don't remember the controls for movement.
Questline for Nations: I think it pretends that a nation questline has finished, probably for testing if the nations will then start to send sieges and take other colonies, and change alliances, which only happens after a nation questline has completed.
Beta Test Mode: Changes a bunch of the script random chances to always be true, probably so that they could be tested without needing to wait for a random chance to actually get lucky.