1917889 - Firefox Nightly: Timezone via JavaScript window.Date API always displays Atlantic/Reykjavik?

Status: RESOLVED DUPLICATE of bug 1666160

(Core :: JavaScript Engine, defect)

Description

[Steve Enright]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:130.0) Gecko/20100101 Firefox/130.0

Steps to reproduce:

Using third-party hosted email service with Firefox Nightly, I noted the email date/time stamps were off from my local time by seven or eight hours. Then switched to production version of Firefox and no issue with displayed time.

1. My system:
   Windows 10
   Processor Intel(R) Core(TM) i7-4700MQ CPU @ 2.40GHz 2.40 GHz
   Installed RAM 8.00 GB (7.73 GB usable)
   System type 64-bit operating system, x64-based processor
   Pen and touch No pen or touch input is available for this display

2. Using Firefox Nightly (version 132.0a1 (2024-09-10) (32-bit)). For comparison, used production Firefox 130.0 (64-bit).

3. Visited this website to troubleshoot displayed date, time, and timezone:

   https://webbrowsertools.com/timezone/

4. Nightly version shows "Atlantic/Reykjavik" date and time and Production version shows true local date and time and zone "America/Los_Angeles".

Actual results:

site reported the following:

Time on Local Machine:
Tue Sep 10 2024 16:40:12 GMT+0000 (Greenwich Mean Time)

Timezone:
Atlantic/Reykjavik

Expected results:

site should have reported the following:

Time on Local Machine:
Tue Sep 10 2024 09:40:01 GMT-0700 (Pacific Daylight Time)

Timezone:
America/Los_Angeles

Comment 1

[Tom S]

You have privacy.resistFingerprinting enabled.

Comment 2

[Steve Enright]

Thanks.