def get_link_label_position(dictionary_key_string):
    """Get the position of a reference-style link label from a dictionary-key string, returning the position in list format.
    
    The link label's position is stored with 3 comma-separated numbers that indicate a link label's *line number*, *left bracket index*, and *right bracket index*. The numbers are stored in the following way: ["1,2,3"]
    
    The key is stored as a string instead of a list or a tuple because:
    
    1. Python does not support lists as dictionary keys.
    2. JSON does not support tuples as dictionary keys.
    """
    
    link_label_position = [ int(list_item) for list_item in dictionary_key_string.split(',') ]
    return link_label_position