What's the Deal with GitHub Spec Kit

I'm really enjoying working with SpecKit, but the tutorials are all still pretty elementary.

Would be great to see how others are handling real world use cases like making incremental improvements or refactorings to a huge legacy code base that didn't start out as a spec driven development hello world project, or situations where you identify additional aspects of the spec midway through implementing the tasks as opposed to before you start implementing the tasks (because the reality is BDUF is still hard), or etc.

Maybe I missed it in the article, but are the specs for the project being talked about available? Would be cool to run it and see how aligned it really makes things (i.e. generate the project multiple times using the same spec)

First thing I noticed when loading the repo: The image doesn't load.

I believe this is a reflection on how things are run. High pressure, no reviews. All to get something out there.