What is the ruling on the inquirer fasting on the days she experienced brown and yellow discharge, knowing that she was unaware these are not considered menstruation, and that she would only perform ghusl after the bleeding stopped, and then the brown and yellow discharge would appear?

The fatwa states that yellow or brownish discharge is considered menstruation if it occurs during the accustomed period or is continuous with blood. If you are certain that you did not make up days when you experienced yellow or brownish discharge that is considered menstruation, then you must make up these days. However, if you are unsure, then nothing is required of you. If you are uncertain whether the yellow discharge was continuous with blood, the default rule is that menstruation persists and has not ceased. However, if you doubt the validity of your fast after it has ended, the default rule is that it is valid and does not need to be made up, because doubt concerning an act of worship after its completion has no effect.

Therefore, you are only required to make up what you are certain you fasted while you were ruled to be menstruating and have not yet made up. If you are unable to make up the fast now due to pregnancy or breastfeeding, there is no blame upon you. Once the excuse is gone and you are able to make up the fast, then make up what is required of you.