What is the ruling on the very light yellow fluid that appears at the end of menstruation? Is it considered a yellowish discharge that necessitates performing ghusl and making up missed prayers?

If a woman sees yellowish or brownish discharge during her customary period, or if it is connected to blood, then this is considered menstruation. Purity is ascertained by one of two signs: complete dryness or the emission of the white discharge (al-qassah al-bayḍā’). Ritual purification (ghusl) becomes obligatory upon seeing purity. As for white discharges, they are not considered menstruation, and if their color changes to yellow, that is not taken into account. One must not succumb to obsessive thoughts (waswas), and the default rule is that menstruation persists when there is doubt about purity, unless the woman is prone to obsessive thoughts.