— Scheme procedure: mu-register-format rest

Registers desired mailutils formats. Any number of arguments can be given. Each argument must be one of the following strings:

Argument	Meaning
‘mbox’	Regular UNIX mbox format
‘mh’	MH mailbox format
‘maildir’	Maildir mailbox format
‘pop’	POP mailbox format
‘imap’	IMAP mailbox format
‘sendmail’	sendmail mailer format
‘smtp’	SMTP mailer format

If called without arguments, the function registers all available formats

— Scheme procedure: mu-strerror err

Return the error message corresponding to err, which must be an integer value.