Should we also suggest the packages app? (the search function on src.fp.o is not very nice)

https://packages.fedoraproject.org/ ?

This is about co-maintaining? Should we put this at the end near the "adding a new package" bit as one of the two paths to being a maintainer?

Is the package-review list worth mentioning as a high traffic list where are package review related e-mails are sent?

package-review@lists.fedoraproject.org

Looks good in general, a few comments but nothing major :)

Should we also suggest the packages app? (the search function on src.fp.o is not very nice)
https://packages.fedoraproject.org/ ?

Good idea, I will add that.

This is about co-maintaining? Should we put this at the end near the "adding a new package" bit as one of the two paths to being a maintainer?

Yes, either co-maintaining or even more informal contribution
in form of bug reports, pull requests and taking part in discussion.
The main idea is that there is much more to packaging
than just having your own package.
Ideally, making changes related to that should be done separately,
not mixed in a pull request about mailing lists.
But I was not happy at all about having scm-commits and package-announce
in the list of "important mailing lists",
as if you could usefully subscribe to those without having automatic processing.
The volume is simply too great.
But on the devel list, an opinion was expressed
that these lists should be mentioned somehow,
so I did some restructuring to find a place to mention them
in a sensible context.

You are right that the fallout from this,
i.e. having co-maintainer related things in one place
and new packages at another
is also strange.
I will see what can be done.

Is the package-review list worth mentioning as a high traffic list where are package review related e-mails are sent?
package-review@lists.fedoraproject.org

Well, since scm-commits and package-announce are mentioned,
it would be weird not to mention this.
On the other hand,
I think the list of important mailing lists should be such
that the newcomer can simply subscribe to all of them.
Making them think which lists are useful and which not is more mental burden,
and there is enough of that in the Joining phase already.

I think a good place to mention this list could be section Read Other Submissions.
Actually, it probably is trying to recommend it,
but somehow list name and a link to its Hyperkitty page is missing.
Maybe due to an error in the wiki import,
Pandoc helpfully replaces some Wiki markup it does not understand with empty strings,
causing issues that look exactly like that.
What if I just insert the list there?

I did the changes as discussed.
I think there is no need for another round of review here,
so I went ahead and merged the updated version.
If there are any concerns about the updated version,
we can always push fixes later.

Thank you for the review!