The Aruna Prashna is part of the Taittiriya Aranyaka of the Krishna Yajurveda.
From the preface of the book "Essence of Taittiriya Aranyaka":
Taittiriya Aranyaka‟ (Part 1) covers 10 chapters of which 6 are
Aranyaka proper. The first chapter of Aruna Prashna deals with the
daily duties of „shrotriya brahmanas‟; Parashara Smriti aptly
details the „...