XCUITest driver supports Appium Settings API. Along with the common settings the following driver-specific settings are currently available:

Name	Type	Description
elementResponseAttributes	string	Comma-separated list of element attribute names to be included into findElement response. By default only element UUID is present there, but it is also possible to add the following items: name, text, rect, enabled, displayed, selected, attribute/<element_attribute_name>. It is required that shouldUseCompactResponses setting is set to false in order for this one to apply.
shouldUseCompactResponses	boolean	Used in combination with elementResponseAttributes setting. If set to false then the findElement response is going to include the items enumerated in elementResponseAttributes setting. true by default
screenshotQuality	int	See the description of the corresponding capability.
mjpegServerFramerate	int	The maximum count of screenshots per second taken by the MJPEG screenshots broadcaster. Must be in range 1..60. 10 by default
mjpegScalingFactor	int	The percentage value used to apply downscaling on the screenshots generated by the MJPEG screenshots broadcaster. Must be in range 1..100. 100 is by default, which means that screenshots are not downscaled.
mjpegServerScreenshotQuality	int	The percentage value used to apply lossy JPEG compression on the screenshots generated by the MJPEG screenshots broadcaster. Must be in range 1..100. 25 is by default, which means that screenshots are compressed to the quarter of their original quality.
customSnapshotTimeout (snapshotTimeout before 1.19.1)	float	Set how much time in float seconds is allowed to resolve a single accessibility snapshot with custom attributes. Snapshots are mainly used for page source generation, XML lookup and custom attributes retrieval (these are visibility and accessibility ones). It might be necessary to increase this value if the actual page source is very large and contains hundreds of UI elements. Defaults to 15 seconds. Since Appium 1.19.1 if this timeout expires and no custom snapshot could be made then WDA tries to calculate the missing attributes using its own algorithms, so setting this value to zero might speed up, for example, page source retrieval, but for the cost of preciseness of some element attributes.
waitForIdleTimeout	float	Has the same meaning as corresponding capability (see above)
animationCoolOffTimeout	float	The amount of time in float seconds to wait until the application under test does not have any active animations. This check is usually applied after each automation action that is supposed to change the state of the application under test, like click one, and blocks XCTest until the transition of the tested application to a new state completes or the cool off timeout occurs. The default value is 2 (seconds). Setting it to zero disables animation checks completely.
snapshotMaxDepth	int	Changes the value of maximum depth for traversing elements source tree. It may help to prevent out of memory or timeout errors while getting the elements source tree, but it might restrict the depth of source tree. Please consider restricting this value if you observed an error like Timed out snapshotting com.apple.testmanagerd... message or Cannot get 'xml' source of the current application in your Appium log since they are possibly timeout related. A part of elements source tree might be lost if the value was too small. Defaults to 50
useFirstMatch	boolean	Enabling this setting makes single element lookups faster, but there is the known problem related to nested elements lookup. Defaults to false.
reduceMotion	boolean	Changes the 'reduce motion' preference of accessibility feature. Defaults to false
defaultActiveApplication	string	Sets the hint for active application selection. This helps WebDriverAgent to select the current application if there are multiple items in the active applications list and the desired one is also one of them. The setting is particularly useful for split-screen apps automation. Defaults to auto, which makes WebDriverAgent to select the application whose element is located at screenPoint location or a single item from the active apps list if the length of this list is equal to one.
activeAppDetectionPoint	string	Defines the coordinates of the current screen point. WebDriverAgent uses this point to detect the active application if multiple application are active on the screen. The format of this value is x,y, where x and y are float or integer numbers representing valid screen coordinates. Setting this value to a point outside the actual screen coordinates might corrupt WebDriverAgent functionality. By default the screen point coordinates equal to 20% of the minimum screen dimension each, e.g. MIN(w, h) * 0.2, MIN(w, h) * 0.2
includeNonModalElements	boolean	Whether returns all of elements including no modal dialogs on iOS 13+. It fixes cannot find elements on nested modal presentations, but it might make visibility attributes unreliable. You could also enable shouldUseTestManagerForVisibilityDetection setting (defaults to false) or simpleIsVisibleCheck capability to improve the visibility detection. This issue may happen between iOS 13.0 to 13.2 (Xcode 11.0 to 11.2). The query issued in includeNonModalElements returns nil with newer iOS/Xcode versions and Appium/WDA return proper elements three without this setting being used. Defaults to false.
acceptAlertButtonSelector	string	Allows to customize accept alert button selector. It helps you to handle an arbitrary element as accept button in accept alert command. The selector should be a valid class chain expression, where the search root is the alert element itself. The default button location algorithm is used if the provided selector is wrong or does not match any element. Example: **/XCUIElementTypeButton[`label CONTAINS[c] 'accept'`]
dismissAlertButtonSelector	string	Allows to customize dismiss alert button selector. It helps you to handle an arbitrary element as dismiss button in dismiss alert command. The selector should be a valid class chain expression, where the search root is the alert element itself. The default button location algorithm is used if the provided selector is wrong or does not match any element. Example: **/XCUIElementTypeButton[`label CONTAINS[c] 'dismiss'`]
screenshotOrientation	string	Adjust screenshot orientation for iOS. Appium tries to return a screenshot and adjust its orientation properly using internal heuristics, but sometimes it does not work, especially in landscape mode. The actual screenshot orientation depends on various factors such as OS versions, model versions and whether this is a real or simulator device. This option allows you to enforce the given image orientation. Acceptable values: auto (default), portrait, portraitUpsideDown, landscapeRight, landscapeLeft.
boundElementsByIndex	boolean	Whether to look up elements with allElementsBoundByAccessibilityElement (default) or allElementsBoundByIndex. This Stack Overflow topic explains the differences. Defaults to false.
keyboardAutocorrection	boolean	Changes the 'Auto-Correction' preference in Keyboards setting. Defaults to false.
keyboardPrediction	boolean	Changes the 'Predictive' preference in Keyboards setting. Defaults to false.
nativeWebTap	boolean	See the description of the corresponding capability.
nativeWebTapStrict	boolean	See the description of the corresponding capability.
nativeWebTapTabBarVisibility	enum	Bypass finding whether the existence of the tab bar before tapping on the element. It could make native web tap faster. If it's visible, tab bar offset will be added without checking the existence of the tab bar. It's invisible, the tab bar offset will be zero. If you want to leave Appium to check and measure the tab bar offset, unset or set detect. Only applicable if nativeWebTap and nativeWebTapStrict are enabled. Unset by default.
nativeWebTapSmartAppBannerVisibility	enum	The same as nativeWebTapTabBarVisibility, this keyword will bypass finding whether the existence of the smart app banner.
safariTabBarPosition	string	Handle offset of Safari tab bar in nativeWebTap enabled interactions. If platformVersion was greater than or equal to 15 and iPhone device, the value is bottom by default. Otherwise top. When the value is top, Appium considers offset as the bar length. iOS 15+ environment can customize the bar position in the settings app, so please adjust the offset with this. Acceptable values: bottom, top
useJSONSource	boolean	See the description of the corresponding capability.