def get_region_labels_txt(regions_file):
    """Get the labels for custom ILAMB regions from a text file.

    Parameters
    ----------
    regions_file : str
        A text file containing ILAMB custom region definitions.

    Returns
    ----------
    list
        A list of custom region labels.

    """
    labels = []
    with open(regions_file, 'r') as fp:
        lines = fp.readlines()
    for line in lines:
        labels.append(line.split(',')[0])
    return labels