> Can someone please develop a piece of software, document/video themselves doing it and explain what/why they are doing parts of the project?

iirc I think Leslie Lamport might've been thinking about making just such a series on TLA+ on the ML... TLA+ is a software specification system he wrote that was popularized by Amazon and Microsoft. It's open and the tools, while rough, are free to use.

If he doesn't go through with it I've been looking for something to teach and I'd like almost nothing more than to teach TLA+ to more people.