What are the key takeaways from “Original Hello World in "B" Programming Language - Computerphile” on Computerphile?

What is this episode about?

The B programming language, a precursor to C, was effectively lost to history until a hobbyist reverse-engineered its compiler. By studying surviving object code and documentation, the project demonstrates how a functional compiler can be built in under 1,000 lines of code, proving that extreme minimalism remains a viable path for portable, low-level software development.