If The Emperor Had a Podcast is a spinoff show that was introduced in Episode 25 of If The Emperor Had a Text-To-Speech Device. The podcast features the Emperor reading books that Custodisi and Wamuudes have gathered from the Black Library (which coincidentally are identical to real-world Warhammer 40,000 books). Various characters may appear as well.
The podcast is presented as a public Vox broadcast to inform the ignorant masses of the Imperium about history, as well as noting the discrepancies and continuity errors between different books (especially those of the older editions of Warhammer 40,000, and particularly old "Chapter Approved" fluff). Novels, meanwhile, are noted to have an eerily omniscient narrator that defies explanation (and usually they butcher the author's name).
The Podcast also serves as a replacement for the in-universe Q&A videos (episodes 12.5 and 18.5) as each Podcast episode has a final segment for answering user-submitted questions about various 40k topics. One ongoing theme is a dispute between the Emperor and Rogal Dorn about which day that tacos should be eaten.