Implementation of the strange "Marker packet" (Tag 10)
An experimental version of PGP used this packet as the Literal
packet, but no released version of PGP generated Literal packets with this
tag. With PGP 5.x, this packet has been reassigned and is reserved for use as
the Marker packet.
The body of this packet consists of:
The three octets 0x50, 0x47, 0x50 (which spell "PGP" in UTF-8).
Such a packet MUST be ignored when received. It may be placed at the
beginning of a message that uses features not available in PGP
version 2.6 in order to cause that version to report that newer
software is necessary to process the message.