The metroBlob property specifies alternative XML content for a shape that SHOULD<31> be ignored. This property specifies a binary serialization of an Open Packaging Conventions container, as specified in [ISO/IEC29500-2:2012]. The package contains an Office Open XML DrawingML document, as specified in [ISO/IEC29500-4:2011], Section 5.
If the shape is modified after it is loaded, Office will delete this information.
opid (2 bytes): An OfficeArtFOPTEOPID record, as defined in section 2.2.8, that specifies the header for this property. The following table specifies the subfields.
A value that MUST be 0x03A9.
A value that is undefined and MUST be ignored.
A bit that indicates whether the metroBlob_complex property, as defined in section 184.108.40.206, exists. If the value equals 0x1, the metroBlob_complex property MUST exist.
metroBlob (4 bytes): The number of bytes of data in the metroBlob_complex property. If opid.fComplex equals 0x0, this value MUST be 0x00000000. The default value for this property is 0x00000000.