def default_pipeline():
    """
    Content of pipeline tab.

    Arguments:
    None

    Return:
    Content items as list
    """
    items = [['Meta', '1', int, 'Meta;' +
        'Session to work:Copy to work:Copy_work,' +
        'Session to backup:Copy to backup:Copy_backup,' +
        'Session to HDD:Copy to HDD:Copy_hdd', 'PLAIN', '', ''], ['Find',
        '1', int, 'Find;Import', 'PLAIN', '', ''], ['Import', '1', int, 
        'Find;' + 'Motion:Motion,' + 'CTF_frames:CTF,' +
        'Compress:Compress,' + 'Meta to work:Copy to work:Copy_work,' +
        'Meta to backup:Copy to backup:Copy_backup,' +
        'Meta to HDD:Copy to HDD:Copy_hdd,' +
        'Frames to work:Copy to work:Copy_work,' +
        'Frames to HDD:Copy to HDD:Copy_hdd,' +
        'Frames to backup:Copy to backup:Copy_backup', 'PLAIN', '', ''], [
        'Motion', '2', int, 'Motion;' + 'CTF_sum:CTF,' + 'Picking:Picking,' +
        'Sum to work:Copy to work:Copy_work,' +
        'Sum to HDD:Copy to HDD:Copy_hdd,' +
        'Sum to backup:Copy to backup:Copy_backup', 'PLAIN', '', ''], [
        'CTF', '2', int, 'CTF;' + 'CTF to work:Copy to work:Copy_work,' +
        'CTF to HDD:Copy to HDD:Copy_hdd,' +
        'CTF to backup:Copy to backup:Copy_backup', 'PLAIN', '', ''], [
        'Picking', '2', int, 'Picking;' +
        'Picking to work:Copy to work:Copy_work,' +
        'Picking to HDD:Copy to HDD:Copy_hdd,' +
        'Picking to backup:Copy to backup:Copy_backup', 'PLAIN', '', ''], [
        'Compress', '2', int, 'Compress;' +
        'Compress to work:Copy to work:Copy_work,' +
        'Compress to HDD:Copy to HDD:Copy_hdd,' +
        'Compress to backup:Copy to backup:Copy_backup', 'PLAIN', '', ''],
        ['Copy_work', '1', int, 'Copy_work;', 'PLAIN', '', ''], ['Copy_hdd',
        '1', int, 'Copy_hdd;', 'PLAIN', '', ''], ['Copy_backup', '1', int,
        'Copy_backup;', 'PLAIN', '', '']]
    return items
