PEP_X.H

The public symbol file NTKRPAMP.PDB for the original release of Windows 10 tells that the kernel is built with the PEP_X.H header at

d:\th.public.fre\ddk\inc

and draws from it the following type definitions:

Line Number	Type	Line Number (PEPFX.H)
72	struct PEPHANDLE__	same
503	struct _PEP_CRASHDUMP_INFORMATION	412
1719	enum _GPIO_PIN_CONFIG_TYPE	1480
1726	enum _GPIO_PIN_IORESTRICTION_TYPE	1487
1733	enum _PEP_ACPI_RESOURCE_TYPE	1494
1746	union _PEP_ACPI_RESOURCE_FLAGS	1507
1766	struct _PEP_ACPI_IO_MEMORY_RESOURCE	1527
1780	struct _PEP_ACPI_INTERRUPT_RESOURCE	1541
1794	struct _PEP_ACPI_GPIO_RESOURCE	1555
1817	struct _PEP_ACPI_SPB_RESOURCE	1578
1832	struct _PEP_ACPI_SPB_I2C_RESOURCE	1593
1843	struct _PEP_ACPI_SPB_SPI_RESOURCE	1604
1857	struct _PEP_ACPI_SPB_UART_RESOURCE	1618
1871	struct _PEP_ACPI_EXTENDED_ADDRESS	1632
1893	union _PEP_ACPI_RESOURCE	1654

The header PEP_X.H itself is not known in any Device Driver Kit (DDK) or Windows Driver Kit (WDK). There is, however, a PEPFX.H which looks to be the public form. If so, it is “missing” 91 lines between its lines 72 and 412, and then another 140 before line 1480.