What is this protocl version sent in the TLS supported_versions extension?

Hi, I am inspecting TLS client hello for a simple connection using Chrome Version 85.0.4183.83 (Official Build) (64-bit). There is unexpected version labeled as "unknown" with a strange code number. I know of TLS versions and their numbers are noted in the standard. I looked at the strange version number and could not figure it out. Can anyone help me identify what is this unknown version number for? Does Chrome do this for any purpose?

This is the version:

Supported Version: Unknown (0x3a3a)

See this screenshot: https://i.imgur.com/NT70mRg.png

qa's avatar
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qa
asked 2020-11-29 17:35:40 +0000
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draft-ietf-tls-grease-01 - "This document describes GREASE (Generate Random Extensions And Sustain Extensibility), a mechanism to prevent extensibility failures in the TLS ecosystem."

What version of Wireshark are you running?

Chuckc's avatar Chuckc (2020-11-29 17:51:20 +0000) edit
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Wireshark version: Version 2.6.10 (Git v2.6.10 packaged as 2.6.10-1~ubuntu18.04.0) Why? Is there anything related to the Wireshark version?

qa's avatar qa (2020-11-29 18:21:16 +0000) edit
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Support for GREASE was added several years ago.
TLS: Add Reserved Extension type from GREASE
Can you open your capture with a newer version of Wireshark (maybe on a different machine) to verify the decode works now? If that works then building a newer version on Ubuntu might help.

Chuckc's avatar Chuckc (2020-11-29 18:50:20 +0000) edit
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