Global attributes | MNX specification

# Global attributes

Type: Dictionary

These are the global attributes available on every object within MNX.

## Attributes

Name | Type | Required? | Description
--- | --- | --- | ---
_c | string | No | An optional comment. This serves a similar function as XML or HTML comments.
_x | An object with user-defined keys, where each value is a vendor dict | No | Optional vendor extensions. This is a place for extra data beyond the scope of what MNX formally supports. If provided, it should be a dictionary that maps vendor keys to dictionaries of data ("vendor dicts"). Vendor keys are strings that essentially serve as a namespace. An example might be a specific notation software package (e.g., "finale"), or a specific community of practice (e.g., "forteNumbers"). We don't maintain a list of known vendor keys at this time, but we may maintain an informal list in the future, once usage has been established. Vendor dicts must be dictionaries. Beyond that, MNX places no requirement on their contents. Implementers are free to design their own data layout within these dictionaries. MNX-consuming software is under no obligation to preserve the data within the "_x" attribute. When an MNX document is transferred between separate MNX software implementations, we expect some software will try to preserve it while other software will discard it.
id | ID | No | An optional ID. This must be unique within the document.