No, I'm fairly sure that was not their intent. It says at the bottom of the readme: NOTE: The sources and build scripts may be added after Unicode Version 14.0

No, I'm fairly sure that was not their intent. It says at the bottom of the readme: NOTE: The sources and build scripts may be added after Unicode Version 14.0.0 has been released (2021), and as time and resources permit. So this repo doesn't have the source currently, despite what it may say earlier in the readme. I'm assuming the TTF file in the release is the actual font, and the "Source code" zip is just an automatic archive of what's currently in the repository.