

The options to password protect it are in the (usually /etc/radicale/)config file und [].
For proper security you could use
type = htpasswd
htpasswd_filename = /etc/radicale/users
htpasswd_encryption = bcrypt
then create a users file with apache tools (htpasswd -c -B users User1) or one of the million online htpasswd file creators.



While you are right in general, you are just creating a file with a <user>:<hashed password> line without any identifying context. So have fun searching the world for where I might have actually used it. Sounds like a really bad use of ressources to create list of passwords.
PS: Yes, as an Arch user I am still pissed that this tool is not available in the repos beside installing the complete Apache server…