Mahabharata 12.159.24

उदक्या ह्यासते ये च ये च केचिदनग्नयःकुलं चाश्रोत्रियं येषां सर्वे ते शूद्रधर्मिणः

udakyā hyāsate ye ca ye ca kecidanagnayaḥkulaṃ cāśrotriyaṃ yeṣāṃ sarve te śūdradharmiṇaḥ

Our plain-language meaning of this verse is waiting for scholar review.