A quick note to say I had no idea Let’s Encrypt is so easy to use. I followed these instructions, but the EFF’s Certbot gives instructions for many sorts of systems.
I thought the tool would generate some confusing configuration file I’d need to edit and move and tweak, but all I had to do was this (on an Ubuntu system where I host a web site): three commands to install the tool, then one to say, “Make this site work with HTTPS.”
I answered one or two yes/no questions and then it just worked.
This is really admirable work. My congratulations and thanks to everyone involved.