hidden files and directories warnings

I received these rkhunter results; what are these files, and are they dangerous? [23:17:48] Checking for hidden files and directories [ Warning ] [23:17:48] Warning: Hidden file found: /etc/.sudoers.tmp.swl: Vim swap file, version 7.4 [23:17:48] Warning: Hidden file found: /etc/.sudoers.tmp.swm: Vim swap file, version 7.4 [23:17:48] Warning: Hidden file found: /etc/.sudoers.tmp.swn: Vim swap file, version 7.4 [23:17:49] Warning: Hidden file found: /etc/.sudoers.tmp.swo: Vim swap file, version 7.4 [23:17:49] Warning: Hidden file found: /etc/.sudoers.tmp.swp: Vim swap file, version 7.4