[tbb-bugs] #16327 [Tor Browser]: NavigatorLanguage API should be spoofed

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#16327: NavigatorLanguage API should be spoofed
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     Reporter:  mikeperry    |      Owner:  tbb-team
         Type:  defect       |     Status:  new
     Priority:  normal       |  Milestone:
    Component:  Tor Browser  |    Version:
   Resolution:               |   Keywords:  ff38-esr, tbb-fingerprinting
Actual Points:               |  Parent ID:
       Points:               |
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Comment (by arthuredelstein):

 This is indeed handled by 'intl.accept_languages'. See the code at:
 https://dxr.mozilla.org/mozilla-central/source/dom/base/Navigator.cpp#409
 I also tested manually and observed that window.navigator.languages always
 matches the 'intl.accept_languages' pref value.

 It would be nice to write a regression test for this. Currently we set
 `intl.accept_languages` to `en-us, en` in tor button when
 'extensions.torbutton.resist_fingerprinting' is enabled. It would be
 possible to write a simple mochitest that sets pref and confirms that it
 is reflected in navigator.languages. But maybe we should put some unit
 tests in torbutton itself, to confirm that the settings are as expected?
 Not sure what the best approach is here.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/16327#comment:2>
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