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Accept-language header in private mode

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Is there any setting to stop accept-language header request, or change it to default in Private mode, with tracking protection enabled.

from https://w3ctag.github.io/private-mode/ drafts Browsers in private mode MUST NOT emit any of the following request header fields: Accept, Accept-Language ...

Is there any setting to stop accept-language header request, or change it to default in Private mode, with tracking protection enabled. from https://w3ctag.github.io/private-mode/ drafts Browsers in private mode MUST NOT emit any of the following request header fields: Accept, Accept-Language ...

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Whose draft is that? It seems rather extreme, but I guess that would be a comment for the discussion thread: https://github.com/w3ctag/design-reviews/issues/101

I notice the stated purpose of that section of restrictions is:

Maintaining server privacy means limiting its ability to identify the user, through "fingerprinting" the client, or associating the user's behavior on one site with that on another (using a mechanism like cookies).

I'm not aware of any preferences that modulate the HTTP headers sent in private mode. There may be extensions that can do that.

There is a preference in testing called privacy.resistFingerprinting which may have some of those effects. However, users have reported some website breakage with that setting, so it probably needs further development. It is expected to be "turned on" in Firefox 59.

More info: https://wiki.mozilla.org/Security/Fingerprinting