Property Override Flag Collection Items

LIBRARY_OVERRIDABLE:

Library Overridable.

Make that property editable in library overrides of linked data-blocks. NOTE: For a property to be overridable, its whole chain of parent properties must also be defined as overridable.

NO_PROPERTY_NAME:

No Name.

Do not use the names of the items, only their indices in the collection.

USE_INSERTION:

Use Insertion.

Allow users to add new items in that collection in library overrides.