A Vendor Specific Data Block (if any) contains as its first three bytes the vendor's IEEE 24-bit registration number, least significant byte first. The remainder of the Vendor Specific Data Block is the "data payload", which can be anything the vendor considers worthy of inclusion in this EDID extension block. For example, IEEE registration number means this is a "HDMI Licensing, LLC" specific data block (contains HDMI 1.4 info), means this is a "HDMI Forum" specific data block (contains HDMI 2.0 info), means this is "DOLBY LABORATORIES, INC." (contains Dolby Vision info) and is "HDR10+ Technologies, LLC" (contains HDR10+ info as part of HDMI 2.1 Amendment A1 standard). It starts with a two byte source physical address, least significant byte first. The source physical address provides the CEC physical address for upstream CEC devices. HDMI 1.3a specifies some requirements for the data payload.