Star Trek: 10 Classified Starfleet Secrets
While exploring space, Starfleet has made a number of discoveries too dangerous to be made public.
In Trek, Starfleet constantly encounters dangerous new technologies, phenomena, and alien societies. Despite this, they are actually surprisingly transparent with their knowledge. Students at Starfleet Academy, for example, learn about the adventures of Kirk's Enterprise, and the many earth-shattering discoveries they made, with little censorship.
However, Starfleet, like pretty much every other organization, has some secrets that they wish to keep hidden. Tech too potentially dangerous to be shared, crimes that Starfleet committed in the past, entire worlds forbidden to visit, and many more classified pieces of information exist, known only to the highest ranking officers in the fleet and the CIA-inspired secret organization, Section 31.
Section 31 itself, since it's conception, has retreated further and further into the shadows until they were virtually forgotten by everyone by the 24th century. Clearly Starfleet has a skill of hiding what they don't want to be known.
This list will count down the ten biggest secrets Starfleet has classified over the years. Secrets so dangerous that they threatened the very existence of the Federation, and sometimes the whole galaxy.
10. Yor
When Discovery's crew traveled to the 32nd century in Star Trek: Discovery's third season, the mirror universe version of Philippa Georgiou started having flashbacks, losing control of her mind, and physically glitching at random intervals, and no one on the ship could figure out what was wrong.
The Discovery crew took this information to Doctor Kovich, who accessed and showed Doctor Culber the classified file of the alien known as Yor. Yor was a Starfleet officer and time soldier who, in 2379, traveled both to the future and to the prime universe from another dimension.
Kovich revealed that his journey to both a different time and a different universe (just as Georgiou had done) caused him to slowly and painfully die as his molecules drifted further away from the time and place they were meant to be.
Interestingly, it's heavily implied that the universe Yor originated from was the rebooted timeline from the new Star Trek movies. Kovich stated that his reality was created by a Romulan mining ship. Fans assume that he was referring to the Narada, Nero's ship from Star Trek (2009).