The numbers mean different things for different sets of elements. Often a 0 means off, false or no, and 1 means on, true or yes.
In the case of sort orders, they are relative to the other numbers in their set. If display order number 1 is missing, element 2 will be in the first position.
The display description setting (defaults to 150) is the number of characters (rounded to whole words); 0 is none.
In some cases, 0 is the normal store setting, and numbers have specific control meanings. These will be described in the setting details.



