Even so, it is clear that the United States sees Sayada as a test of the concept before it is deployed in more contested zones. The United States Agency for International Development “awarded a three-year grant to the New America Foundation to make this platform available for adoption in Cuba,” said Matt Herrick, a spokesman for the agency, which recently stirred controversy by financing a Twitter-like social media site in Cuba. As for the mesh project, Mr. Herrick said, “We are reviewing the program, and it is not operational in Cuba at this time. No one has traveled to Cuba for this grant.”

Radio Free Asia, a United States government-financed nonprofit, has given $1 million to explore multiple overseas deployments. The countries involved have not been revealed, Mr. Meinrath said, adding, “I can’t talk about specific locations because lives could be at risk.”

The citizens of Sayada — population 14,000 — are more focused on using the mesh for local governance and community building than beating surveillance since President Zine el-Abidine Ben Ali was ousted in 2011, said Nizar Kerkeni, 39, a resident and professor of computer science at the nearby University of Monastir.

The mesh network blankets areas of town including the main street, the weekly market, the town hall and the train station, and users have access to a local server containing Wikipedia in French and Arabic, town street maps, 2,500 free books in French, and an app for secure chatting and file sharing.

The mesh is not linked to the wider Internet, Professor Kerkeni says — a point in his favor when he invites families to connect in this Muslim community. “Some parents ask me if it is safe to connect to the server,” he said. “They don’t allow their little children to connect to the Internet. I say, ‘I know it’s safe.’ ”

The mesh software, called Commotion, is a major redesign of systems that have been run for years by experts across Europe, said Mr. Meinrath, who is now director of the New America Foundation’s X-Lab. The idea, he said, was to take the technology out of what he calls “the geekosphere” and make it accessible to the public. (Commotion is available to download free from the project’s website.)