Settings.cfg

TUTORIALS_EDITOR_ENABLE = False

I believe this one and the one underneath it, by the way they sound, enable to game to show the VAB and Flight tutorials when the game is first started, which explains why they don't appear if you start a new save.

TUTORIALS_FLIGHT_ENABLE = False

VAB_USE_CLICK_PLACE = True

Not entirely sure. Perhaps there's another part placement method?

VAB_USE_ANGLE_SNAP = True

Snaps to angles in the VAB and SPH. C key by default changes this value in-game.

VAB_ANGLE_SNAP_INCLUDE_VERTICAL = False

Interesting. I want to test this out. Instead of only snapping on a spinning axis around the parts, I imagine this allows parts to be snapped at a vertical axis (up and down in VAB)

VAB_CAMERA_ORBIT_SENS = 0.04

This and the next 5 settings are camera sensitivity related.

VAB_CAMERA_ZOOM_SENS = 0.1

FLT_CAMERA_ORBIT_SENS = 0.04

FLT_CAMERA_ZOOM_SENS = 0.5

FLT_CAMERA_WOBBLE = 0.1

FLT_CAMERA_CHASE_SHARPNESS = 1.5

FLT_CAMERA_CHASE_USEVELOCITYVECTOR = True

Forces the chase cam (not available in .17 as far as I can tell) to use your velocity vector as it's chase point.

FLT_VESSEL_LABELS = True

Shows vessel labels at a distance. F4 in-game by default changes this value.

SIMULATE_IN_BACKGROUND = True

I believe this value changes whether or not the game will progress while minimized/alt-tabbed/out of focus.

MAX_VESSELS_BUDGET = 250

Amount of vessels able to be active before others are deleted(?)

CONIC_PATCH_DRAW_MODE = 3

This and patch limit were discussed previously. Allows view of (slightly inaccurate) future orbit and encounter figures.

CONIC_PATCH_LIMIT = 5

SHOW_PWARP_WARNING = False

Whether or not the game shows the warning about large ships when entering physical warp modes. Changes to false after first warning.

CALL_HOME = False

ET phone home. Not sure what this does.

DONT_SEND_IP = False

A disclaimer and agreement is shown at first launch whether or not to send your IP, among other information, to the developer for development and I assume demographic purposes. Can be true or false depending on your answer.

CHECK_FOR_UPDATES = True

Exactly as it says. Automatically checks for updates on launch.

SHOW_CONSOLE_ON_ERROR = False

I assume this is a developer tool to show the developer console when an error occurs. Disabled by default.

AUTOSAVE_INTERVAL = 300

Interval in seconds (I assume) between auto-saves in-game.

AUTOSAVE_SHORT_INTERVAL = 5

I'm not sure

SHOW_SPACE_CENTER_CREW = True

I assume this is to enable or disable the Kerbal scientists walking around the VAB and such.

SHIP_VOLUME = 0.09689867

The following 8 settings are related to volume and are relative to your in-game volume settings.

AMBIENCE_VOLUME = 1

MUSIC_VOLUME = 0.8

UI_VOLUME = 1

VOICE_VOLUME = 1

SOUND_NORMALIZER_ENABLED = True

SOUND_NORMALIZER_THRESHOLD = 1

SOUND_NORMALIZER_RESPONSIVENESS = 16

SOUND_NORMALIZER_SKIPSAMPLES = 0

SCREEN_RESOLUTION_WIDTH = 1920

This and the height are self-explanatory. Your in-game resolution after the initial launch screen is generated and the game begins to load.

SCREEN_RESOLUTION_HEIGHT = 1080

FULLSCREEN = True

Whether or not the game sets itself to full screen when launched.

ANTI_ALIASING = 8

Anti-aliasing quality. 8 is highest.

TEXTURE_QUALITY = 0

Texture quality. Assuming 0 is highest since I have mine on full.

SYNC_VBL = 0

Wait for vertical sync. Has several settings. 0 is no sync.

LIGHT_QUALITY = 8

Lighting quality. 8 is maximum I believe.

SHADOWS_QUALITY = 4

Changed in the registry values for some people, not an in-game setting due to graphical limitations. 0-4 (5 in registry sets this value to 4).

FRAMERATE_LIMIT = 180

Limits framerate to user choice for whatever reason. 180 is max. Cannot be unlimited by default.

FALLBACK_PART_SHADERS = False

Compatibility mode for older hardware. Checking this in the graphics options may ruin some transparency textures. I made this mistake.

PLANET_FORCE_SHADER_MODEL_2_0 = False

I believe this setting forces the planets to use shader model 2.0 or 3.0, depending on the value. I believe it uses 3.0 by default.

PLANET_SCATTER = True

Value of terrain scattering in the options, combined with the amount in the option below.

PLANET_SCATTER_FACTOR = 0.5

INPUT_KEYBOARD_SENSIVITITY = 2

I might change this for testing purposes. This is the input sensitivity of keyboard clicks on flight models.

Thanks to Aphox [1]