Opinion Cal.com has closed its commercial codebase, abandoning years of AGPL-3.0 licensing in a move that has alarmed the developer community that helped build it and sent ripples through the broader open source world. "Open source is dead," says Cal.com co-founder and CEO Bailey Pumfleet. But my conversations with top open source developers such as Linux kernel maintainer Greg Kroah-Hartman suggest it is not. And I really don't think it is. Punfleet made this declaration because the company is moving its main program from the GNU Affero General Public License (AGPL) to a proprietary license, as he sees AI as too much of a threat to the program's security. Or, as he told me, "AI attackers are flaunting that transparency," so " Open source code is basically like handing out the blueprint to a bank vault . And now there are 100× more hackers studying the blueprint." If that sounds familiar, it should. It's an ancient argument that letting people read your code automatically makes it more vulnerable.…