Oob = stands for Order of Battle, this is syntax telling the game to call the respective oob file (which can be found in history/units/) for that nation (and depending on the amount of action the country sees: the oob for a specific YEAR.) oob files are usually split based on whether or not they're land or naval units (defined as ,) naval units are also split up by whether or not a player owns DLC, with those who do own it using and those who don't using files. (Or, if you installed Visual Studio Code and the extensions I recommended, you can go into that, press CTRL+SHIFT+P, and type out 'Preview' before clicking the preview world map option, allowing you to view the in-game map and all its debug info without having to launch! Seen below.) You can hover over a state in-game while in debug-mode in order to read off all information including state ID.

Capital = defines the location of the country's capital via a State ID, in-game, the regions that are given names (e.g the American states for example) are states, with provinces being the much smaller areas that make up individual states.