There are weird PHP errors affecting the blog tonight. One visible is
Warning: Undefined variable $silent in /usr/home/rpearse/public_html/weblog/wp-content/plugins/footnotes-for-wordpress/wp-footnotes.php on line 156
I would guess my hosting company has broken something. I will investigate tomorrow. My apologies.
Update: The hosting company, the excellent Pair.com, advised me that they upgraded PHP 7.4 to PHP 8.2, as 7.4 is end of life. This caused the break. They fixed it by adding two lines to the top of the .htaccess file in the root /weblog directory:
AddType application/x-httpd-phpx .php Action application/x-httpd-phpx /fcgi-bin/php7_wrapper.sh
It looks as if WordPress have not updated their code to the latest version of PHP. I hope that this will be fixed soon.