sysclean(8) is a system tool designed for help system administrator to keep their OpenBSD clean after upgrade.
It walks the installed system and compare to a reference system, reporting to the user additional things in the installed system.
The purpose is to point any elements that wouldn’t be present if a fresh install was done, instead of an upgrade.
This seems like a useful tool.
I don’t know what the number people append next to Unix utils is, and at this point I am too afraid to ask.
Man page section. There’s 9 separate sections for man pages, based on how they’re used (system utilities, user utilities, programming functions, etc). For utilities with man pages in multiple sections, the number is used to let you know which section to read. For utilities with only a single man page, you can omit the number:
man 8 sysclean
man sysclean
Also, every section has a «intro» manpage which explains what it is about.