[sp332]

DNT is practically defunct. https://en.wikipedia.org/wiki/Do_Not_Track#History

In January 2019 W3C Tracking Protection Working Group concluded work on Do Not Track standard citing "insufficient deployment of these extensions" and lack of "indications of planned support among user agents, third parties, and the ecosystem at large." In February 2019 Apple Safari 12.1 was released without support for DNT to avoid it being used as a "tracking variable."

[fooqux]

You can tell how bad the lack of support / teeth is when people start using the flag to not track them as an extra way of tracking people. That's extremely telling... but sadly not unexpected by many of us.

[cpeterso]

Should Mozilla remove the DNT header from Firefox like Apple did in Safari? When DNT does nothing except give trackers one more bit of fingerprint entropy, is there any value in users still allowing users to send DNT? "DNT: I am one of those people who does not want you to track even though I know you will."

[sp332]

I think it's fine since it's opt-in. Maybe there could be a warning in the UI though.