Mahabharata 12.171.4

अत्राप्युदाहरन्तीममितिहासं पुरातनम्निर्वेदान्मङ्किना गीतं तन्निबोध युधिष्ठिर

atrāpyudāharantīmamitihāsaṃ purātanamnirvedānmaṅkinā gītaṃ tannibodha yudhiṣṭhira

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