$strMetaBoxID
$strMetaBoxID : string
Stores the meta box id(slug).
Provides the space to store the shared properties for meta boxes.
This class stores various types of values. This is used to encapsulate properties so that it helps to avoid naming conflicts.
$intEnqueuedStyleIndex
Stores the index of enqueued styles.
The index number will be incremented as a script is enqueued regardless a previously added enqueue item has been removed or not. This is because this index number will be used for the script handle ID which is automatically generated.