It turns out that on some hosts a URL like:

https://example.com/wp-content/plugins/syntax-highlighting-code-block/vendor/scrivo/highlight.php/styles/default.css

Will get blocked by Nginx due to it thinking that highlight.php is a PHP file, when it is actually a directory.

We should rename the directory to highlight-php when creating a build, perhaps.