What do the numbers in the FreeBSD mana in the links to other manas section mean?

Question

FreeBSD

Here is an excerpt from the IPFW mana:
LINKS
cpp(1), m4(1), bridge(4), divert(4), dummynet(4), ip(4),
ipfirewall(4), protocols(5), services( 5), init(8), kldload(8),
reboot(8), sysctl(8), syslogd(8)
Actually, these numbers in parentheses are different, but I couldn't google anything about them.

Answer 1

Apparently bad Google) The
number in the bracket specifies the category to which the command belongs. Used to organize management to avoid duplication as the same commands can belong to different categories. Used, for example, like this man 8 reboot
List of categories:

1. - executable programs and shell commands;
2. - system calls;
3. - library calls;
4. - device files (usually located in /dev);
5. - file formats;
6. - games;
7. - macro packages and agreements;
8. - system administration programs;
9. - kernel procedures

Answer 2

Start with man manyou don't even know how to work with manuals, the help for the man command itself will open up a lot of new things for you.