I heard about the Mark Hofmann forgeries only a few years ago when a sibling mentioned them to me in passing. I didn't look up Hofmann or read anything about the forgeries right away because, as juicy as it all was, I expected nothing less from our modern prophets, seers, and revelators.
Page 1 of the "Salamander Letter"
In a nutshell, Hofmann was an amazing forger who produced a number of documents relating to early LDS Church history. These forged documents compromised the Church's position of authority to such an extent that Gordon Hinckley, who was serving as a councilor to Spencer Kimball, got directly involved in the purchasing and hiding of the Hofmann forgeries. There's plenty of literature out there on topic (like this, this, or this) if you'd like all the nefarious details.
We can all agree that Mark Hofmann did terrible things and hurt a lot of people - killing two - but his story should find its way onto everyone's lists of doubts because of how badly the Church handled him. First off the Church showed zero power of discernment with regards to Hofmann's evil intents. The Church showed zero power of discernment with regard to the content of invented documents. Instead, the Church's behavior indicates that top leaders find the existence of such documents entirely plausible. The Church proved that it was willing to spend hundreds of thousands of (early 1980s) dollars to control compromising documents. And top leadership was more than eager to keep the content of the forgeries a secret from the general Church membership and the world in what can only be described as outright deception.
How could our prophets, seers, and revelators be so naive? How could they be so shady? Why should we trust the Church's whitewashed version of history when it's obvious that they themselves do not? Isn't it cause for concern when our top leaders are so preoccupied with an potential expose of early Mormon insanity? It's frankly incriminating.