One cute feature of markdown I'd not noticed before: there's no syntax for images *without* a description (i.e. alt text).

https://spec.commonmark.org/0.31.2/#images
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Today I learnt that you can mix HTML inline in markdown! For example, the following is valid.
Foo <hr/>
I'd assumed that you needed HTML separately, like ``` blocks, but no: https://spec.commonmark.org/0.31.2/#raw-html
Admittedly HTML is very restricted on most sites, but it's helpful for SSGs.
A cute systemd feature to get the system clock roughly correct: if the system time is before the compilation time of the systemd binary, it moves the clock forward to that time!
https://lwn.net/Articles/714355/
I'm not sure if I should use the term "text diff" or "textual diff" to refer to a conventional, line-oriented diff of text in difftastic.
Any opinions? Which seems clearer to you?