[tbb-bugs] #30683 [Applications/Tor Browser]: Properties in dom/locales/$lang/chrome/ allow detecting user locale

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#30683: Properties in dom/locales/$lang/chrome/ allow detecting user locale
-------------------------------------+-------------------------------------
     Reporter:  gk                   |      Owner:  tbb-team
         Type:  defect               |     Status:  new
     Priority:  High                 |  Milestone:
    Component:  Applications/Tor     |    Version:
  Browser                            |   Keywords:  tbb-fingerprinting-
     Severity:  Normal               |  locale
Actual Points:                       |  Parent ID:
       Points:                       |   Reviewer:
      Sponsor:                       |
-------------------------------------+-------------------------------------
 z3t reported a bunch of issues on HackerOne regarding detection of user
 locale with the help of `dom/locales/$lang/chrome/` properties. PoCs done
 by z3t:

 `dom/dom.properties`:
 https://people.torproject.org/~gk/tests/tor_form_locale_leak.html
 `layout/xmlparser.properties`:
 https://people.torproject.org/~gk/tests/tor_domparser_locale_leak.html
 `layout/MediaDocument.properties`:
 https://people.torproject.org/~gk/tests/tor_image_locale_leak.html

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/30683>
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