What Is an Example of Objective Knowledge?
There are puzzles present here. I believe the questioner is asking for a specific claim that is objectively true, such as something like “At sea level, water boils at 100 degrees centigrade.” The idea being that such a claim would be true regardless of who made it.
The questioner might, however, be asking what it means for a thing to be objectively true; that would be a horse of a very different color. Someone adhering to the correspondence theory of truth would look for a specific relationship between the truth-barer and the real world; but there are other possible definitions of “truth” that would look for different parameters. And then we would still have to wrestle with the concept of objectivity.
If the questioner is asking for an example of objective knowledge assuming that a thing has to be true in order to be known, then he or she must first establish a definition for “knowledge” that differs from the widely-accepted though seemingly debunked justified-true-belief definition, as a belief entails a point of view of the belief holder, and something with a point of view would seem not to be objective.
Now, someone (Karl Popper) might claim that a book contains knowledge that would be knowledge even if all the consciousness in the cosmos were suddenly extinguished and then evolved again billions of years later. That re-evolved consciousness could figure out how to decode the book and acquire the knowledge contained there, concluding that the knowledge (at least in the intervening years) had no point of view and was therefore objective.
It seems to me, however, that “knowledge” without a consciousness to process or possess it is not knowledge at all, but some kind of simple existence. Even the identification of anything beyond total randomness requires consciousness, and consciousness has no comprehensible aspect anterior to a point of view, which is the antithesis of objectivity.