Trackable A Trackable is something that ARCore can track and that Anchors can be attached to.

Anchor	Describes a fixed location and orientation in the real world.
ArCoreApk	Static methods for managing the status of ARCore on the device.
AugmentedImage	Describes the current best knowledge of a real-world augmented image.
AugmentedImageDatabase	Database containing a list of images to be detected and tracked by ARCore.
Camera	Provides information about the camera that is used to capture images.
CameraIntrinsics	Provides information about the physical characteristics of the device camera, for the camera image (CPU) or texture (GPU).
Config	Holds settings that are used to configure the session.
Frame	Captures the state and changes to the AR system from a call to `update()`.
HitResult	Defines an intersection between a ray and estimated real-world geometry.
ImageMetadata	Provides access to metadata from the camera image capture result.
LightEstimate	Holds information about the estimated lighting of the real scene.
Plane	Describes the current best knowledge of a real-world planar surface.
Point	Represents a point in space that ARCore is tracking.
PointCloud	Contains a set of observed 3D points and confidence values.
Pose	Represents an immutable rigid transformation from one coordinate space to another.
Session	Manages AR system state and handles the session lifecycle.
Stub	An empty class to create a stub apk for the purposes of playstore auto-update of ARCore

Anchor.CloudAnchorState	Enumeration of all Cloud Anchor States
ArCoreApk.Availability	Describes the current state of ARCore availability on the device.
ArCoreApk.InstallBehavior	Controls the behavior of the installation UI.
ArCoreApk.InstallStatus	Indicates the outcome of a call to `requestInstall()`.
ArCoreApk.UserMessageType	Controls the message displayed by the installation UI.
Config.CloudAnchorMode	The cloud anchor mode in `Config`.
Config.LightEstimationMode	Select the behavior of the lighting estimation subsystem.
Config.PlaneFindingMode	Select the behavior of the plane detection subsystem.
Config.UpdateMode	Selects the behavior of `update()`.
LightEstimate.State	Light Estimate States.
Plane.Type	Simple summary of the normal vector of a plane, for filtering purposes.
Point.OrientationMode	Indicates the point orientation mode.
TrackingState	Describes the tracking state of the Trackable.

com.google.ar.core