I am reading the SEC prospectus Coinbase's initial public offering, available here. On page 20, it is written:
Many crypto assets have concentrated ownership or an “admin key”, allowing a small group of holders to have significant unilateral control and influence over key decisions relating to their crypto networks, such as governance decisions and protocol changes, as well as the market price of such crypto assets.
I am not familiar with the existence of such "admin keys" that allow some users to unilaterally change the properties of a token or a blockchain. Would anyone care to fill me in or provide some sources I can read?