Actually this is a godsend for me. I've been meaning to experiment with Rust, and I keep a ~/NOTES directory with these kind of notes. Hopefully I'll contribute something soon!
This looks like a useful tool, but at the moment I consider vimwiki to be better suited for my needs, even if it does not support encryption like theca.
Seems the URL is down.
Looks to be this one though; <a href="https://github.com/rolandshoemaker/theca" rel="nofollow">https://github.com/rolandshoemaker/theca</a>