okay so basically, here is when you can park:
AFTER 7PM but BEFORE 6AM (11 hours that are "safe")
AFTER 9AM but BEFORE 4PM (5 hours that are "safe")
- OR -
if it's a Weekend, any time is OK.

HOWEVER,
Do not try to leave your car there for any longer than 120 minutes, or any times outside of the 120 minute window you started, because parking enforcement may believe that your car has been there longer than 2 hours and it's all about what they perceive - best not to give them any bright ideas or else you'll have to argue it in traffic court.
(That said, the parking meters may have times of operation outside of which it would be OK to park longer than 2 hours. Make sure to check the meter, because if this 2 hour enforced window is only in effect on weekdays between 9am and 4pm you may be allowed to park overnight unmolested.)

But then we get to the exception signs that have been taped on beneath. The owner of this property can designate any exceptions they want, because as owners of the property they get to decide who is or is not authorized to be there.

The first exception sign:
Notice it's pointing to the left. It's overriding the "NO PARKING" blanket rule and specifically allowing tour buses to use the area, which is fine.
2023-08-30 was a Wednesday.
On that Wednesday evening through Thursday morning at 6AM, a tour bus is allowed to park to the left of this signpost overnight whereas it would not have been allowed otherwise, which is pretty cool and convenient for whoever needs that bus.

The second exception sign:
2023-08-31 was the aforementioned Thursday.
The time listed on it is a bit hard to read but I believe it's saying PM.
So, overnight Thursday night into Friday morning, only tour buses are allowed to park to the right of the signpost.
Friday morning after 6AM, it's business as usual again, which means parking is allowed for regular paying customers from 9AM to 4PM, and then once again ok for customers to park after 7AM and leading into the weekend.

This brings us to the third exception sign:
It's also pointing to the right, and reserving the space for tour buses only through its duration.
The duration it's setting aside is the evening of Saturday, September 2nd 2023 beginning at 6pm and proceeding for 24 hours until Sunday evening. The intervening time before this sign went into effect, people were allowed to park all the way through Saturday afternoon. Quite reasonable. However, we now see the fourth sign...

The fourth exception sign seems to be tacked on either as a corrective measure for not reserving enough time to begin with or perhaps due to compliance issues about needing to only assign exceptions in stretches of time no greater than 24 hours or something. It picks up immediately where the third sign left off and carries the exception for tour buses only until Monday, September 4th 2023, at 6AM - whereupon the default configuration kicks back in again.

So, while it takes a little parsing, it's not too difficult to figure out whether or not you can park there at any given time. Sounds like they had a big event requiring some bus traffic for a while though. Hope everybody had a great time with whatever it was!

Seeing as I work for a towing company, understanding these things and being able to explain them to people is relevant to my business, since towing people for not following posted parking procedures is one of our areas of operation.