This line and the above should probably be one single line. The "And" is already connecting the two parts.

This sentence could use a comma to break it up.

"through ports and packages" or "through the ports collection and packages"

"In section..." --> "In the section..."

"...file system structure can refer to..." --> "...file system structure refer to..."

Looks like that is UCL, not ACL?

"As a general rule, these files..." --> "As a general rule, configuration files..."

Because last thing we talked about weren't the config files, but sysctl and before that it was hier(7).

"But some applications like..." --> "Some applications like..."

The comma should be a semicolon.

Should /etc/fstab be in this table? It's one of the files I always have to update.

It might be worth it to mention that the MIB is hierarchical and hence, specifying a prefix prints all the nodes hanging from it:

sysctl compat.ia32
compat.ia32.maxvmem: 0
compat.ia32.maxssiz: 67108864
compat.ia32.maxdsiz: 536870912

At some point in this section I would mention that sysctl -d gives you a description of the tunable node (if available):

sysctl -d kern.dfldsiz
kern.dfldsiz: Initial data size limit

"Values are set in ..." --> "Values are set using a variable=value syntax".

"...will be add it to..." --> "...is to add it to..."
"...executing..." --> "...by executing..."

"To determine whether or not a service is running, use status." --> "To determine if a service is running, use the status subcommand."

This sentence could be read as if we, FreeBSD developers, did not have time or motivation to support this for all services :-)
I would rewrite this ias

*Not all services support this feature".

Do we really need details on construction of startup scripts? Most people shouldn't have to modify them or write new ones.

/home/user/... would be more future-proof (14.0 no longer defaults to /usr/home). /home is a symlink in earlier releases so works there too.

need a comma

/home again; should agree if changed above.

After 614, I would add: "The periodic tasks are initiated by entries in the system crontab, shown above."

..."and the configuration by..." --> "...and its configuration resides in..."

FreeBSD provides a set of system management scripts to check status of various subsystems, perform security-related checks, rotate log files, etc.
These scripts are run on a periodic basis: daily. weekly, or monthly.

I think this is confusing; it could just as well be describing cron and /etc/crontab. The intro here could point back to the "periodic" entries in /etc/crontab. The periodic(8) page isn't much better. I can try to come up with something if necessary.

It is probably worth mentioning that the output of the periodic scripts is emailed to root by default, and therefore it is best to read root's mail or alias root to a mailbox that is monitored. The output can be redirected to a file instead; see periodic(8).

"...the first step will be ..." --> "...he first step is..."

Maybe "edit" rather than "open" (hinting that any editor could be used)?

"...all that need to..." --> "...all that needs to..."

"...manage where the results of script execution are sent." --> "...specifies where to send the results of the script execution."

"...to root by default..." --> "...to root..."

We are already saying "By default" at the beginning of the sentence.

"...or to other emails separated by spaces..." --> "...or to other emails, add the email addresses separated by spaces to [.filename]#/etc/periodic.conf#:"

"...lines to [.filename]#/etc/periodic.conf#, man:newsyslog[8] will rotate these..." --> "...lines to [.filename]#/etc/periodic.conf#. man:newsyslog[8] will rotate these..."

"The facility..." --> "A facility..."

"The facilities..." --> "Facilities..."

s/factory/facility/

man:newsyslog[8]

The default owner and group are root and wheel respectively.