Sketch files start with a Header Section which starts with the following codes:

Offset Size Data Description

0000 ID 37 00 00 10 UID1: Header Section layout

0004 ID 6D 00 00 10 UID2: File kind

0008 ID 7D 00 00 10 UID3: Application ID

000C L 9C F9 08 55 UID4: Checksum of UID1, UID2 and UID3

0010 Section Table Offset Section

0014

The Section Table Section may contain the following sections, usual in the given order.

Identifier Section Always found

7D 00 00 10 Offset of the Sketch Section Yes

89 00 00 10 Offset of the Application ID Section Yes