The Tectonic documentation tool, ironically, has no documentation itself. That needs to be fixed.

One day the docs will be written in TeX, but for the proximate future I think it is more practical to write them in Markdown so that they can appear on the website — with Unicode and decent CSS, the presentation will be sufficiently readable. Translating from MD to TeX will require some effort in the future, but it will just be a bit of busywork, not anything fundamentally challenging.

• the config file (cc Support HTTP proxies #59)
• the command line options
• the idea behind the "bundle" approach
• what to do if a needed file is missing or too old
• (lack of) biblatex/biber support
• location and structure of cache directory (cc Document the location and structure of the cache directory #45)
• "why not just use latemk?" etc
• emphasize that Tectonic is its own engine, not something that runs other engines
• how to emulate latexmk -pvc (cf Continuous mode #82 and other issues)