From:  WaltS48 <schw01@REMOVEverizon.net>
Date:  27 May 2019 22:49:18 Hong Kong Time
Newsgroup:  news.mozilla.org/mozilla.support.calendar
Subject:  

Re: Time Zone

NNTP-Posting-Host:  63.245.210.105

On 5/26/19 9:05 PM, Marc Moisan wrote:
> Good day,
> 
> I would like to know how I could create a new time zone?
> 
> Specifically, I would like to create "Etc/GMT+12" which as a seafarer I sometime need when crossing the Pacific Ocean.
> 
> I looked around but I can't find where the time zones are located to either add of modify them, I would appreciate the help.
> 
> Cheers,
> 
> Marc Moisan, CD, PLog
> 

Have you tried modifying "calendar.timezone.local" in about:config to 
"Etc/GMT+12"?

My setting is "calendar.timezone.local;America/New_York"

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