File attributes are user defined, as opposed to file properties that are system defined.
File attributes are key-value pairs, use them to store anything you want.
Stored as an uninterpreted list of bytes.
Integer in range
Number of attributes is unlimited.
Size of all the attributes together is capped in 64KB.
The size of all attributes is the sum of each attribute key plus the size of each attribute value.
If you need more space for some file attributes, consider storing the data in the body of child files instead.