I wanted to improve my website's (not this one) performance by using images in AVIF and JPEGXL format,
but I kept getting 403 Forbidden when trying to access them.
I thought there was some kind of bug regarding Caddy's file_server. Turns out I was wrong.
Somehow the permissions on the .avif and .jxl files got changed and Caddy was literally forbidden from accessing them.
The fix? Just give Caddy the appropriate permissions:
chown -R caddy:caddy path-to-your-files