- You may be looking for the comic story.
Hidden Human History, sometimes abbreviated as H3, was a weekly podcast that ran on Earth sometime in 2018 that talked about historical events, hosted by Bethany Brunwine. Subjects talked about on the show included, but were not limited to, famous serial killers and "wars you don't learn about in school". It had been running for roughly a year before the Thirteenth Doctor arrived in Sheffield.
The show was enjoyed by the Doctor's companions. Graham O'Brien recalled how Grace had it playing around the house all the time. Ryan Sinclair began listening at the insistence of his grandmother, while Yasmin Khan was turned onto it by a friend at work. Yaz praised the show as being "really well done", and that it felt more like "historical gossip" than "sitting in a lesson". Ryan later admitted that it took a little while for the show to get its "polish", and that the earlier episodes were a "bit dull".
When the Thirteenth Doctor brought Team TARDIS to Guelder in the early 16th century, Yaz, Ryan, and Graham all identified it as being around the time the Guelders wars took place, as they'd learned from the podcast, much to the Doctor's amazement, and jealousy.
As Team TARDIS proceeded on a journey to various times and places, following the trial of the Stilean flesh eaters, the Doctor's companions realised that all of the historical events they had been passing through on their investigation had all been covered on the podcast. Deciding to pay a visit to creator Bethany Brunwine at her home in London, the crew were shocked to learn that she was the leader of the flesh eaters they had been tracking, having taken on a humanoid appearance after years of consuming their flesh, and becoming near-immortal as a result of consuming the Doctor's Time Lord blood during their first encounter. Brunwine explained that, after years of living among her former prey and developing a fondness for them, she created Hidden Human History, inspired by her prior encounters with the Doctor and her words about history; "all of the actual people get lost in the numbers and the names". (COMIC: Hidden Human History)