What is the ruling on the discharge of brown secretions and black blood after the sixth day of the menstrual cycle, and is the woman considered to have broken her fast by that?

Any blood seen by a woman at a time when it could be menstruation is considered menstrual blood. So, if the duration of menstruation exceeds her usual period, it is still considered menstruation, as long as it does not exceed fifteen days. As for brownish discharges (al-kudrah), they are considered menstrual blood if they occur during the habitual period or are continuous with the blood.