I reinstall emacs by compiling its source and then sudo checkinstall. I found checkinstall creates a file-rw-r--r--  1 root root 44628516 Apr 22 19:19 emacs_24.5-1_amd64.deb-rw-r--r--  1 root root 56991208 Apr 22 19:19 backup-042220151919-pre-emacs.tgzDoes checkinstall  create a backup file regardless of which software it installs, or it depends on specific software (e.g. emacs) (maybe depending on the specific Makefile?)?What is the backup file for? Shall I keep it, and when can I discard it? How shall I use it in case it is needed? 
What is the backup file created by checkinstall for?
software installation;checkinstall