What is the ruling regarding the dowry (Mahr) of a Mukataba (a contractually freeing slave)?

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If the female slave is a Mukataba, the ruling is similar to the others, with the exception that her dowry belongs to her because it stems from her own earnings, and her earnings belong to her. The value of her child is also obligatory upon the master according to the well-known narration. Abu Bakr stated that this value should be given to her so she may use it toward her manumission contract (Kitabah).