mlock 8:2007f~dfsg-7 (ppc64el binary) in ubuntu focal

 IMAP (Internet Message Access Protocol) is a method of accessing
 electronic messages kept on a (possibly shared) mail server.
 .
 The UW (University of Washington) IMAP toolkit provides the c-client
 mail-handling library supporting various network transport methods,
 file system storage formats, and authentication and authorization
 methods.
 .
 This package contains a program to lock mailbox files to avoid
 corruption.