The whole thing is odd though because the clock software must be quite sophisticated to adjust to individual member's time zones and display their 'midnight'.
Maybe I'm wrong but I'd have thought a simple countdown clock could be found to simply display the hours and minutes left until a deadline disregarding time zones.
It's the exact opposite. It's easier to use the Web browser time zone as the guide. That's a set phrase in programming language. So the add-on just refers to the phrase that's used for the web browser time. If you then say midnight for the countdown timer expiry, you get (expiry - current web browser time) = time to show
If you want to use a set time zone you have to start considering daylight saving problems. Some time zones are half hours or 45 minutes off and some places do follow daylight saving, but the closer to the equator you get, the fewer places follow daylight savings because they don't get the big fluctuations in sunset sunrise times and so on.
So (expiry time in set time zone - gmt offset) plus or minus daylight savings depending on location within country = time to show if member has correctly selected city closest to them rather than the one that's correct for their time (think of the sign ups that say London UK instead of morroco for example, or in my case, Sydney when they're in Brisbane. Same time zone and correct time in winter, but once summer arrives Brisbane/Queensland don't do daylight savings because they're much closer to the equator. NSW and Victoria also fall in the same time zone but they do follow DST and hence the time is off... now visit Adelaide and they are 30 minutes behind NSW and Victoria and either 30 or 90 minutes behind Queensland depending on the time of year.)
And now you'll see why it's easier not to show it relevant to time zones.
Yes, back in XF 1.x the countdown clock did work, but seeing it up for that 1 hour difference was a manual process made by us setting the clock to the midnight +/- an hour as needed. We'd usually guess and check, then amend accordingly. But that was a time when the system time on servers could be used as a field code. Nowadays less of that is available to developers and more is browser time rather than system time that the software can access. Security designs/features mean you can't now access these codes.
