That unknown mystery switch toggles airplane mode.

I can't afford one. Why? It's complicated.

My guess for the unknown L and Zero slider is a volume of the chime.   0 = no noise, L = loud.

The week indicator is quite handy for some countries . In Denmark we would never say “the week starting October 5th”, we would say week 41.

That is an emergency stop switch.

I have news for you, it is still far from the most complicated mechanism put into watches, but it is quite beautiful at the same time.

Very interesting!  Ty for sharing

Favorite one is sunrise/sunset time based on city

FYI. That L and O toggle switch on the reverse of this watch.
• L stands for "Lock" or "Chime" (often corresponding to L'heure or enabling the striking mechanism to function normally).
• O stands for "Overt" or "Silence" (disabling the chiming/repeater functions entirely to prevent acoustic disruption, typically referred to as night mode or silence).

The only thing it doesn't have is a "countdown timer". One you can set for a specific amount of time so it'll start when you start it and it'll chime when that timed event ends.
And because it's not got a countdown timer, I won't buy one. But then, you've not said how much this watch costs.
I'm guessing it's going to be a little more than my Casio I got 20 odd years ago that keeps perfect time as it's linked to the time signal, has a solar panel on the front and will never need a battery? i.e. It'll be well north of £1 million.
But you lost me when you turned the watch over to see the back of it and all that astrological mumbo jumbo.  😅🤣😂

maybe the light for the back dial..

i wouldnt mind having one

Which week of the year it is could be used when you are filling in timesheets. But if you own this watch i think others are filling in timesheets because they work for you

The "L" and "0" are the choice between long chime (L) or just hourly (0).  The switch with "W" and "H" is to select which winding barrel you want to tackle: the one for the watch itself or the one for the chimes.  I assume W stands for Westminster and H for Horology.

So, how do
You set the time/ complications? 18:35

Someone should replicate this but in Quartz.

on display today in milano

With regard for the comment that you don't know why anyone would need to know the week of the year, where I work and in many other companies, they use the weeks of the year in project planning all the time - some go as far as having 13 months, each of 4 weeks, to better divide up the year - and go back to the word month's origins being the same as those for moon. The names of the months used to make a lot more sense too - there's a reason September to December sound a lot like the words for seven to ten (In the Latin based romance languages anyway), and they were months 7-10 until Julius and Augustus Caesar went meddling with the calendar.

Conveniently, my Garmin watch not only can draw a full calendar for the month in the screen, which is already extremely useful, but this calendar also includes the week numbers. There are at least 3 different conventions for how the weeks of the year are numbered, so I wonder which one they baked into this watch movement.

L = Loud
0 = Silent

This makes the minute repeater go silent like an iphone!

The toggle is probably there to silence the watch from chimes. Nobody wants to find a noisy watch at dinner parties.

L and O- lunar and ocean maybe?