What are “#” properties?
This one's more out of curiosity than anything.
If you look at the Form API Reference, you can see that all properties have number signs/hash marks (#) at the start of the key.
My question is, why is it like this? Why bother having these hash marks in front of property names, other than "That's the convention somebody somewhere decided", and to occasionally cause people grief when they forget to add one?
Quite curious. Thanks!