The speaker talks about building FPGA bitstreams with open source tools, which was previously a difficult task that required vendor-specific tools. He discusses the open source FPGA toolchain, an example FPGA-based system, and the insights and pain points they encountered during development. They also talk about Litex, an open source Python-based FPGA system-on-chip builder, and how they customized it for their system, including adding their own custom cores. The speaker also provides a GitHub link for the source code and an outlook on future steps they plan to take.