I tried learning using several different resources, but what did it for me was the nix pills (https://nixos.org/guides/nix-pills/). I'd say it's becoming a bit outdated now with the nix standalone command, but the fundamentals are still mostly the same.
I was kinda surprised to see that the development repos are hosted using mercurial (https://hg.slitaz.org/). I don't remember seeing other Linux distros using mercurial instead of git for development. The repos are apparently mirrored on GitHub but I don't see a lot of development happening there.
Currently, my main concern with YAML is that, by the spec, comments are not attached to a particular node (see https://yaml.org/spec/1.2/spec.html#id2767100). As a result, a lot of YAML parsers (like https://github.com/yaml/libyaml and https://github.com/chyh1990/yaml-rust) only filter out the comments during the parsing phase. This makes it less than ideal for a use-case where the configuration file is expected to be modified by both programs and humans.
TOML makes it more trivial to associate comments with a node. This is mainly because the language is simpler though, as the spec is not explicit about that (https://toml.io/en/v1.0.0#comment).
The project depends on `libspeechd-dev`/`speech-dispatcher-devel`, but there's no mention of support for voice commands. Does the framework support speech recognition? That could be pretty neat.