def hdrtxt(xmethod, dmethod, opt):
    """Return ``hdrtxt`` argument for ``.IterStatsConfig`` initialiser.
    """

    txt = ['Itn', 'Fnc', 'DFid', u('ℓ1'), 'Cnstr']
    if xmethod == 'admm':
        txt.extend(['r_X', 's_X', u('ρ_X')])
    else:
        if opt['CBPDN', 'BackTrack', 'Enabled']:
            txt.extend(['F_X', 'Q_X', 'It_X', 'L_X'])
        else:
            txt.append('L_X')
    if dmethod != 'fista':
        txt.extend(['r_D', 's_D', u('ρ_D')])
    else:
        if opt['CCMOD', 'BackTrack', 'Enabled']:
            txt.extend(['F_D', 'Q_D', 'It_D', 'L_D'])
        else:
            txt.append('L_D')
    return txt
Return ``hdrtxt`` argument for ``.IterStatsConfig`` initialiser.