Prashna-1-1-oṃ sukeśā

Sri Shankara’s Commentary (Bhashya) translated by S. Sitarama Sastri

Om, adoration to the Paramâtman, This Brâhmana is begun for the purpose of explaining at length the drift that has been expressed by the mantras. The story of the sage questioning and the sage replying is for the purpose of eulogising knowledge. Thus it praises knowledge, by saying that it should be acquired by men who have been observing Brahmacharya and residing in the house of the preceptor for a year, and who have performed tapas, and that it should be imparted by preceptors but little short of omniscient, like Pippalâda, etc., and not by anybody whosoever; and by the indication of such means as Brahmacharya their observance is directed; Sukesa by name and son of Bhâradvâja; Saibyah, son of Sibi; Satyakâma by name; Sauryâyani ] the son of Sûrya (sun) is Saurya and his son is Sauryâyani. This form (with a long vowel ending) is Vedic license; Gârgya, one born of the family of Gârga; Kausalya by name. Âsvalâyana, the son of Asvala; Bhârgava, one born of the family of Bhrigu; strictly the gôtrâpatyam of Bhrigu (vide, Pânini); Vaidarbhi, born in Vidarbha; Kabandhî by name; Kâtyâyana, son of Kâtya; his great-grandfather being alive, the suffix denoting uva pratyayam is used (vide, Pânini). All these intent on Brahman, i.e., believing in the Apara Brahman as supreme and devoted to its practice seeking after the highest Brahman, i.e., wishing to attempt, as they could, to attain that eternal knowable, approached the worshipful preceptor Pippalâda, with loads of samit in their hands, for the purpose of knowing that, thinking that he would explain all to them.

Links
Various resources on the Prashnopanishad
Upanishad Series – Kena Upanishad Commentary by Swami Chinmayananda