InDesign Book
From Just Solve the File Format Problem
Adobe InDesign in addition to the document format, can save into a Book format, combining multiple documents together which can be export as a single export.[1]
File Information
INDB files have similar header to the document format and begin with bytes 06 06 ed f5. Version identifier is at 0x1D or at 29th byte, ascii BOOKBOOK at byte 16.[2]
