The account has no incognito mode (left) and the account has an incognito mode integrated (right).
YouTube's incognito mode will be integrated directly into the 'Accounts' section of the application. When in this mode, the incognito icon will replace the avatar from the 'Accounts' section.
Currently Google is testing this mode in certain accounts. In the near future, YouTube updates with new features will be officially released to all users.
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