Gif data block. Custom blocks are not supported.
Values
BFrame(frame:Frame)
Gif frame block. Note that this block does not contain link to graphic control extension of Frame even if it is present. GraphicControl extension Block commonly present right before frame Block.
BExtension(extension:Extension)
Additional extension block. This Block does not supported in 87a Gif specification version.
BEOF
End of File block. Represents end of Gif data.