/private/var/mobile/Library/Preferences/com.apple.springboard.plist

This property list file contains most preferences for SpringBoard. Below is a list of known and valid preference keys for SpringBoard.

Key	Path	Type	Description
NumberOfTimesSetupSiriShown	Root	Integer	Number of times that the user has attempted to summon Siri before it has been enabled.
SBAllowAutoPIP	Root	Boolean	Allow media to be displayed in Picture-in-Picture mode automatically.
SBBacklightLevel2	Root	Integer	Brightness.
SBButtonForceFeel	Root	Integer	Force level for devices with solid-state home buttons.
SBComingFromUserPowerDown	Root	Boolean	Whether SpringBoard is being loaded on a cold boot.
SBControlCenterDemo	Root	Boolean	Enable a Radar button in the AirPlay menu of Control Center.
SBShowRSSI	Root	Boolean	Show Wi-Fi connection strength as a numeric value in the status bar.
SBShowGSMRSSI	Root	Boolean	Show cellular connection strength as a numeric value in the status bar.
SBDontLockAfterCrash	Root	Boolean	Don't respring to the lock screen.
SBPlaySoundOnDeviceWake	Root	Boolean	Play a sound when the device wakes up (?).
SBDontLockEver	Root	Boolean	Quite literally does not allow the device to lock, ever. Pressing the lock button does nothing, but you can still power off the device by holding it down.
SBStoreDemoAppLock	Root	Boolean	Usually set by an internal configuration profile, this key locks down the device for use in retail demos. See Smart Sign.
SBDisableMailAutoLaunch	Root	Boolean	Prevents Mail from running in the background until the app is opened.
SBDisableProximity	Root	Boolean	Disable use of the proximity sensor in apps that support it (Phone, FaceTime Audio, etc.).
SBDisableNotificationCenterBlur	Root	Boolean	Disable the blur effect in Notification Center.
SBHideLowPowerAlerts	Root	Boolean	Suppress low power alerts when the device reaches critical battery levels.
SBDidShowReorderText	Root	Boolean	Whether SpringBoard has told the user how to move icons around.
SBUseSystemGestures	Root	Boolean	Use the built in navigation gestures (Five-finger pinch, four-finger swipe, etc.) on iPads.
SBDontDimOrLockOnAC	Root	Boolean	Device will never dim or lock while connected to an external power source.
SBShowVictoria	Root	Boolean	Show the Nike+ Running app on supported devices. See Victoria.
SBDisableAutoDim	Root	Boolean	Never dim before automatically locking.
SBDisableHomeButton	Root	Boolean	Disables the home button. Usually used in conjunction with SBStoreDemoAppLock.
SBRingerMuted	Root	Boolean	Whether the ringer is muted or not.
SBControlCenterEnabledInLockScreen	Root	Boolean	Whether Control Center can be accessed from the Lock Screen.
SBDisableLiveIcons	Root	Boolean	Disables dynamic icons on the Home Screen, like Clock.
SBPrototypeSettingsEnabled	Root	Boolean	Whether SpringBoard's prototype settings can be accessed.

More keys exist, but are mostly undocumented. For an longer list, albeit without descriptions, try here.