This is an unordered collection of cool stuff I found around the web, which I thought are cool but have probably not looked at in more detail yet. Maybe I will get around to it at some point, and maybe you will find something useful in there!
A similar list can be found on Henning’s website at lexodexo.de/dinge-die-mir-otto-geschickt-hat.
An API for building a bunch of different diagram-from-code tools such as mermaid and graphviz: https://kroki.io/
A tool to make nice-looking reports and similar from notebook-style or less of a notebook-style input, allowing interactive diagrams in the HTML output: https://quarto.org/ https://quarto.org/docs/interactive/
Visualization of destinations reachable by direct trains from many european train stations: https://direkt.bahn.guru/
This tool tries to make C++ compilation errors from GCC easier to understand: https://gcc-explorer.com/
A diff-tool explicitly made for source code which compares syntax trees instead of lines, producing much nicer diffs! https://github.com/Wilfred/difftastic
A debugger that allows stepping backwards in time. It actually works, and I found a real bug with it! https://rr-project.org/
To use this with ROS 2, a config file is needed, which I found out here: https://github.com/rr-debugger/rr/issues/2868#issuecomment-849390080
(More recent versions seem to require wrapping the config in an additional
<dds> ... </dds>)
Way nicer code listing in LaTeX than using the “listings” package: https://ctan.org/pkg/minted