The plymouth daemon
The plymouthd daemon is usually run out of the initrd. It does the heavy lifting of the plymouth system, logging the session and showing the splash screen.
The plymouth is used to send commands to plymouthd that control its behaviour.
The following options are understood:
Show summary of options.
Redirect console messages from screen to log.
Do not daemonize.
Output debugging information.
File to write debugging information to.
Set mode to either boot or shutdown.
Write the PID of the daemon to a file.
Fake kernel commandline to use.
TTY to ues instead of default.