It's FOSS - https://itsfoss.com/barcelona-open-source/
Brief: Barcelona city administration has prepared the roadmap to migrate its existing system from Microsoft and proprietary software to Linux and Open Source software.
According to the news report, the city plans to first replace all its user applications with alternative open source applications. This will go on until the only remaining proprietary software will be Windows where it will finally be replaced with a Linux distribution.
Barcelona will go open source by Spring