See DISPATCHER_HEADER (geoffchappell.com) for more info for dispatcher header.

0: kd> dt nt!_DISPATCHER_HEADER ffff848d`b817f580+0x40
   +0x000 Lock             : 0n393217
   +0x000 LockNV           : 0n393217
   +0x000 Type             : 0x1 ''
   +0x001 Signalling       : 0 ''
   +0x002 Size             : 0x6 ''
   +0x003 Reserved1        : 0 ''
   +0x000 TimerType        : 0x1 ''
   +0x001 TimerControlFlags : 0 ''
   +0x001 Absolute         : 0y0

Any object with DISPATCHER_HEADER on its head can be waited upon. The kernel waiting API KeWaitForSingleObject and KeWaitForMultipleObjects.

Waiting here refers to dispatcher waiting. Meaning if the wait cannot be satisfied immediately, the thread would be placed into a waiting state with a KWAIT_BLOCK chaining all waiters of said resource. The thread is then context-switched out of the processor.

Type

The Type field is an enumeration with type KOBJECTS. WDK does not contain the definition of KOBJECTS.

The following table lists the KOBJECTS enumeration, captured from ReactOS:

//
// Kernel Object Types
//
typedef enum _KOBJECTS
{
    EventNotificationObject = 0,
    EventSynchronizationObject = 1,
    MutantObject = 2,
    ProcessObject = 3,
    QueueObject = 4,
    SemaphoreObject = 5,
    ThreadObject = 6,
    GateObject = 7,
    TimerNotificationObject = 8,
    TimerSynchronizationObject = 9,
    Spare2Object = 10,
    Spare3Object = 11,
    Spare4Object = 12,
    Spare5Object = 13,
    Spare6Object = 14,
    Spare7Object = 15,
    Spare8Object = 16,
    Spare9Object = 17,
    ApcObject = 18,
    DpcObject = 19,
    DeviceQueueObject = 20,
    EventPairObject = 21,
    InterruptObject = 22,
    ProfileObject = 23,
    ThreadedDpcObject = 24,
    MaximumKernelObject = 25
} KOBJECTS;

Value	Name	Structure	Versions
0x00	EventNotificationObject	KEVENT	all
0x01	EventSynchronizationObject	KEVENT	all
0x02	MutantObject	KMUTANT	all
0x03	MutexObject (proposed)	KMUTEX	3.10 only
	ProcessObject	KPROCESS	3.50 and higher
0x04	QueueObject	KQUEUE	3.50 and higher
0x04 (3.10);0x05	SemaphoreObject	KSEMAPHORE	all
0x05 (3.10);0x06	ThreadObject	KTHREAD	all
0x07	SpareObject (proposed)		4.0 to early 5.2
	GateObject	KGATE	late 5.2 and higher
0x06 (3.10);0x07 (3.50 to 3.51);0x08	TimerObject (proposed)	KTIMER	3.10 to 3.51
	TimerNotificationObject	KTIMER	4.0 and higher
0x09	TimerSynchronizationObject	KTIMER	4.0 and higher
0x0A	Spare2Object		4.0 and higher
0x0B	Spare3Object		4.0 and higher
0x0C	Spare4Object		4.0 and higher
0x0D	Spare5Object		4.0 and higher
0x0E	Spare6Object		4.0 and higher
0x0F	Spare7Object		4.0 and higher
0x10	Spare8Object		4.0 and higher
0x11	Spare9Object		4.0 to 6.1
	ProfileCallbackObject	KPROFILE	6.2 and higher
0x07 (3.10);0x08 (3.50 to 3.51);0x12	ApcObject	KAPC	all
0x08 (3.10);0x09 (3.50 to 3.51);0x13	DpcObject	KDPC	all
0x09 (3.10);0x0A (3.50 to 3.51);0x14	DeviceQueueObject	KDEVICE_QUEUE	all
0x0A (3.10);0x0B (3.50 to 3.51);0x15	EventPairObject	KEVENT_PAIR	3.10 to 6.2
	PriQueueObject	KPRIQUEUE	6.3 and higher
0x0B (3.10);0x0C (3.50 to 3.51);0x16	InterruptObject	KINTERRUPT	all
0x0C (3.10)	apparently unused		3.10 only
0x0D (3.10 to 3.51)	PowerStatusObject (proposed)	KPOWER_STATUS (proposed)	3.10 only
	apparently unused		3.50 to 3.51
0x0E (3.10 to 3.51)	ProcessObject	KPROCESS	3.10 only
	apparently unused		3.50 to 3.51
0x0F (3.10 to 3.51);0x17	ProfileObject	KPROFILE	all
0x18	Timer2NotificationObject	KTIMER2	6.3 and higher
0x19	Timer2SynchronizationObject	KTIMER2	6.3 and higher
0x18 (5.2 to 6.2);0x1A	ThreadedDpcObject	KDPC	5.2 and higher
0x10 (3.10 to 3.51);0x18 (4.0 to 5.1);0x19 (5.2 to 6.2);0x1B	MaximumKernelObject