When Mark Zuckerberg, the chief executive of Meta, announced last year that his company would release an artificial intelligence system, Jeffrey Emanuel had reservations.

Mr. Emanuel, a part-time hacker and full-time A.I. enthusiast, had tinkered with “closed” A.I. models, including OpenAI’s, meaning the systems’ underlying code could not be accessed or modified. When Mr. Zuckerberg introduced Meta’s A.I. system by invitation only to a handful of academics, Mr. Emanuel was concerned that the technology would remain limited to just a small circle of people.

But in a release last summer of an updated A.I. system, Mr. Zuckerberg made the code “open source” so that it could be freely copied, modified and reused by anyone.

Mr. Emanuel, the founder of the blockchain start-up Pastel Network, was sold. He said he appreciated that Meta’s A.I. system was powerful and easy to use. Most of all, he loved how Mr. Zuckerberg was espousing the hacker code of making the technology freely available — largely the opposite of what Google, OpenAI and Microsoft have done.

“We have this champion in Zuckerberg,” Mr. Emanuel, 42, said. “Thank God we have someone to protect the open-source ethos from these other big companies.”

Mr. Zuckerberg has become the highest-profile technology executive to support and promote the open-source model for A.I. That has put the 40-year-old billionaire squarely on one end of a divisive debate over whether the potentially world-changing technology is too dangerous to be made available to any coder who wants it.