What are these certificate (inside of administration area)place holder meant for

I cannot find any information on online manual (which is IMHO missing lot's of info) is placeholder for certificate files.
Where these certificates are used? Where in my understanding there can be different certificates for different connections in example one set for HTTPS, one set for LDAP and one set for database (like MySQL) connection. So this are could be also more informative, hopefully you can improve this one in near future as well.