webmin.txt

# vhost settings are stored here (plaintext mysql password, among others)
/etc/webmin/virtual-server/domains/<longassnumber>

# certs/keys (backups I guess) and some related config
/etc/webmin/webmin/*

# if you replaced the ssl cert of the main website and fucked up and then restored the backup, and THEN webmin fails to load,
# it needs restarting too. the piece of shit.
systemctl restart webmin # fu

# webmin refuses to load because https is fucked again. disable it:
nano \e[38;5;226m/etc/webmin/miniserv.conf\e[0m # ssl=1 -> ssl=0
systemctl restart webmin

# to then fix it you can tell it to use the main vhosts' certificate for webmin/usermin etc services too
VirtualMin (pick right host) -> Server Configuration -> SSL Certificate: "copy ssl certificate to services" or "set as default services certificate", one of those might work

# If that fails with a "Failed to save service certificates : Service webmin is not installed", edit
\e[38;5;226m/etc/webmin/miniserv.conf\e[0m again to set ssl back to 1 but \e[1mDo Not\e[0m restart the webmin service. The script
 where that error originates just checks the config apparently? Regardless, try hitting the button again.
Afterwards, the service will try restarting itself (because it has a [new] cert) and you might get more
 errors and the interface might Windows3.1 on you but whatever. https might work again.

If firefox keeps redirecting to https even though ssl was disabled in the webmin conf, "Forget this site" in
 history->find site, right-click.

If you didn't get that error, great!
Set ssl=1 back in \e[38;5;226m/etc/webmin/miniserv.conf\e[0m
 and then systemctl restart webmin again.

# Iffff you now get SSL_ERROR_NO_CYPHER_OVERLAP or somesuch,
 maybe webmin doesn't understand the type of SSL keys used by the site, this happened with ECC keys.

Kick it some more if needed, wtf knows.

=== MySQL backups ===

Crontab:
  /etc/webmin/mysql/backup.pl
calls
  /usr/libexec/webmin/mysql/backup.pl
runs
  backup_database
which is defined in
  /usr/libexec/webmin/mysql/mysql-lib.pl
containing the part that looks at settings, around line 1576
The settings are stored in
  /etc/webmin/mysql/config
$ grep backup /etc/webmin/mysql/config