The really tricky problem is when a package must modify an existing shared resource. Such as appending lines to an existing config for example. This is current

The really tricky problem is when a package must modify an existing shared resource. Such as appending lines to an existing config for example. This is currently solved by having applications support both a config file and a config.d directory. The primary owner (package) of the resource modifies the conf file, while secondary packages drop their own config in conf.d/${package}. Numerous examples exist: logrotate, rsyslog, apache, nginx, systemd and apt come to mind.