Update 1/19/2021: We have updated and expanded the information contained here in a new blog post. Please go here to read it: All you need to know about automatic email forwarding in Exchange Online
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Updated Jan 19, 2021
Version 6.0
Blog Post
Hi,
TR :Is sent to 'Outside the organization' and 'x-ld-processed' header contains ''ExtFwd'' can be used to control OWA “Start/Stop Forwarding” method or “forwardingsmtpaddress” set by Administrator.