1. The installer should give one the option to set the system's clock to UTC as well as GMT (for what it's worth Windoz uses GMT and in some FOSS OSs one can choose either).

2. If one leaves it on default English but sets the place to x country, the system will be in English, time will be the time of that particular x country, but the date will be in the language spoken in that x country. The date should be in the system's language.

Edit:

I mean:

If the system's language is set to English, on the login screen and the little popup (when one hovers the time), the date should read ... " Sunday, July 16, 2017"

Interestingly, if the system's language is English, the calendar is indeed in English as well (as it should be).

I've just edited my hart out to make it intelligible

PS: If the system's language is English, neither should the keyboard switch to whatever language based on location.

1) Admin point of view: You have ${LC_TIME} available
2) User point of view: You can't cram every detail into an installer
3) It's good to have a hint which locale You are supposedly in

When should an American Sunday start in France? And how
will we call it? 'French Sunday' or 'Dimanche'?

Calendars and Time-Measurements are an intercultural and global
nightmare. However You decide: There will always be discontent.
It's a question of pride and stupidity.

For example: Jewish, Christian and Islamic Dates alone are intellectual torture.

Therefore: Let each individual decide. Else people will get murdered, maybe.
"It is known".

Say one travels ... not a question of pride or anything like that. It's a technicality rather.

It's good to have a hint which locale You are supposedly in

Of course. One might want a nearby mirror. Which, sometimes but not always, is faster.

Interestingly, if the system's language is English, the calendar is indeed in English as well (as it should be).

Interestingly, if the system's language is x, the calendar is indeed in x as well (as it should be).

I'm a human living on planet Earth. I'm agnostic of anything else.

But in OpenSUSE time, calendar, language .... works as it should. Not on Neon yet. But hey.