A fan created a compelling and elaborate theory about the quasi-mythical "missing" Easter egg from Guardians of the Galaxy -- and while filmmaker James Gunn was impressed with it, he admitted that the Easter egg in question was entirely unintentional.
The theory tied some readings on a display in the movie to the Enigma-Force, a mystical energy field that permeates the Microverse, a subatomic universe. As the name implies, no one truly understands it. In a sense, it is the Microverse, and its first priority is survival. It does not (and perhaps cannot) act directly; rather, it works through the Time Travelers to protect and preserve the Microverse.
A facet of the Enigma-Force, calleed the Omni-Power, can allow anyone to become the superhero Captain Universe. Both the Enigma-Force and the Omni-Power are quasi-sentient and cannot be used for evil.
You can see the full theory in the Reddit post embedded above.
Per the Marvel Wiki, "Captain Universe is not one person. In one sense, it is not a person at all--it is the Uni-Power (an aspect of the Enigma Force) and a manifestation of the Universe itself, a sentient energy field that seeks out people in great peril and bonds with them. In another sense, it is every person--it is the potential for heroism that lives in each of us. When the Uni-Power chooses a partner, it endows that person (or, rarely, persons) with the powers, memories, and costume of Captain Universe. The partner can use the powers of Captain Universe until the peril is surmounted. However, if the partner tries to use those powers for personal gain or for evil, the Uni-Power immediately deserts him or her or them.
"There is no apparent pattern in Captain Universe's appearances or accomplishments. In one universe (and possibly in all universes), it is the Guardian of Eternity, the sum of all life, and is thus responsible for protecting all life in existence."
Intentional or not, one has to wonder, with a filmmaker as immersed in Marvel minutia as Gunn is, whether he might try to tie up that thread by incorporating some of these characters or ideas to 2020's Guardians of the Galaxy vol. 3.