Aldus Placeable Metafile
From Just Solve the File Format Problem
Aldus Placeable Metafile (APM) is a container format for Windows Metafile format. It adds a header that supplies suggested placement and scaling information.
Format
APM files have a 22-byte header, followed by a standard Windows Metafile.
Identification
Files begin with a 4-byte signature: D7 CD C6 9A
.