It turns out, just as I was ready to push the button on publishing this thing, that Jekyll doesn’t generate tag pages for you.
It almost does - the amount of effort to create an “other pages with this tag” page is about 20 seconds, but it doesn’t actually do it.
There are seemingly some plugins, but none of them are allow-listed by GitHub Pages.
So, instead, I’ve had to create a tag
folder, and fill it up manually with a series of short <tag-name>.md
files. Like some sort of Neanderthal.
Ah well, the whole point of documenting more stuff is to learn.