The issue here is that the «Earth-Life» is kind of a «fake» existence;
Physical-Existence is something of an Illusion;

«All things are made of matter.» Traditional Newtonian-Physics
«All matter is made of energy.» Quantum-Physics
«Matter is just solidified energy.» A Time-Traveller
«Matter is actually condensed Light-Frequency.» -Ken (YTC: Theoria Apophasis)

Then there are also different «time-lines» so «looking at history» is also fruitless;
You would also need a co-ordinate system that also identifies the time-line;
FarSight hasn't done any projects specific to the Mandela-Effect for some reason.
Rise.TV has (they are also another Remote-Viewing Organisation/Group).
Although Rise don't teach how to do it as far as I am aware; FS has instructions;
FS wants you, yes, YOU, to learn how to do Remote-Viewing for yourselves...!

P.S./Addendum: Even I could be considered «alien» given the fact that I have literal memories from before I ever experienced this particular «universe» (and Earth-Life) itself; the physical-bodies are just «vessels» (alien-term) or «meat-suits» (term used by some) or «biological space-suits» (term used by Terence de Malahèrre whose ISBE was the SAME one that once inhabited the «flesh-Avatar» known as the famous Jesus) or «biological mech-robots» (a term that I have personally used to describe our existence) so to say that I am this physical-body and look like this physical-body is erroneous or at least not in full-context; the physical-body is only but a temporary form; my «real» self is actual formless.

In physics, astronomy, there are four known major properties of existence: The Weak Force (known for the «decay» effect which results in what is called a «half-life»), the Strong Force (known for its «bonding» effect which «resists» against the «decay» effect), Gravity (the force where large bodies of mass in outer-space are attracted to other large bodies of mass), and Magnetism... actually, more specifically, they are as follows...:
--> Gravitational Force (Gravity)
--> Electro-Magnetic Force (Electro-Magnetism)
--> Strong Nuclear-Force (Strong Force)
--> Weak Nuclear-Force (Weak Force)
They are all part of Astro-Physics or just plain Physics; Flat-Earth was also an incredibly elaborate psy-op in order to make people believe «doesn't exist» (especially aliens).

Oh, and, the «size» of this Earth, I suspect, is actually much, Much, MUCH «BIGGER» than a mere 25K miles circumference, leading to obvious «measures» that SEEM to «prove» that Earth «flat» plane, but, if you think this sort of stuff is hard to wrap your head around, just wait until you see these Glitches in the Matrix that will be really Mind-Blowing...
https://odysee.com/@alanthier001:7/Glitches-In-The-Matrix---Complete-Edition:4

Additionally... THIS is THE «Target» that EVERYBODY who's doing Remote-Viewing will WANT to do for reasons that will be obvious after the on-going Target-Layer Reveals...
https://www.farsightprime.com/forums/remote-viewing-practice-forum/72348-target-http-www-quantum-note-com-black-hole-html

What we can see on video are the reptilian tongues of various prominent figures. They walk among us.

Thanks for your answer, it was easier to understand now. But how can they be visible to some and not to others?

For similar reasons as to why cats and snakes can see in the infra-red and others cannot; for similar reasons as to why dogs can hear what most humans cannot; it's related to both DNA and Frequency (or Resonance-Frequency).

Here is a Homework-Assignment: Pineal-Gland & Psychic-Abilities.

So some people can do it, but not everyone? I am a simple person but I try to be in higher frequencies, because I feel good then. Still, I have never had the ability to "see", however, I sometimes feel and know things without knowing how it happened. Can I learn it?

Everyone can if they weren't disabled in function; just like everyone can walk unless they're a paraplegic; everyone would also be able to fly if they had wings, but, humans aren't birds, and, are not equipped with the DNA that grows/sprouts wings.

And all of existence certainly revolves around frequencies; higher resonance-frequencies are certainly much more pleasant than lower spiritual-frequencies; some people don't like the use of the word «levels» but that is precisely what they are: Ranges (Levels).

And you can definitely develop the ability to see.
Even I, myself, used to be Clariaudient; it was one of the reason why I didn't bother «talking» because I could already «hear» what people said right before they actually said it verbally; this was when I was younger of course, and, I hear that my «parents» (one set of them) tried to get me to talk and I just wouldn't talk until I was somewhere around the age of four (then they also said that once they got me to start talking that they then couldn't get me to shut up). I am sure this woman has versions for clairvoyance on her channel, but, for all intents and purposes, once you are of an adult-age then learning or restoring the ability/abilities are a bit different...

Not saying anyone specific

Thank you, I'll look into that.