I actually find them a very clever workaround to a technologic minor issue. Opinions.

I want to see the SSID and my IP on the lock screen, preferably below the date/mobile network name. How do I go about it?

The lockscreen layout is defined in file "/usr/share/lipstick-jolla-home-qt5/lockscreen/Lockscreen.qml"

You need to create elements for your shown info there, for example just above the "Clock { }" element.

Then you need some scripting to fish out the required info. IP address is easy, and I'd imagine you can also get the SSID out without too much problems.

Thanks, Juice One more silly question: how do you people know these things? Where do I look in the future before having to resort to asking?

Some suggestions:
1. deny 2G connections (to block low security) mode, detect IMSI catchers or provide more information about connections
2. block certain phone numbers (black list) against incoming call
3. silent mode where only calls/SMSes from VIP numbers comes through
4. show time and date in clock and calendar icons like on Nokia N9
5. configure LED patterns like on Nokia N900
6. grouping of contacts

Just about all the stuff you see on your UI are under "/usr/share/", it goes for both applications you install and the SFOS components that make up all the niceties of the device.
Just doing a "ls -l" there shows you pretty much... and find/grep gives you a lot of nice places to start hacking

QML is so tweak-friendly, you can immediately see the results of modifications. And if you botch something, it is easy to restore, just remember to have ssh available all the time you tweak something

UI tweaks, for example require you to restart lipstick after modifying the QML's, just "killall lipstick" is enough to activate your new file.

Looking at that, you will appreciate how hacker friendly the device really is, you can accomplish so much just looking at the QML's and making a small change here and there

OK so the short answer is, "by poking around the device." It's not like I am missing 3 m tall neon letters somewhere saying, "OS tweaks **HERE**!"

you actually need some kind of developer mind to make mods/tweaks anyway.

Did I not mention that SW development is what I do for a living?
I am just not familiar with all ins and outs of everything. I never heard if lipstick, for example.

Well, SailfishOS tweaks/patches are mostly just qml mods. So to know what files are used by application you can do some rpm magic. rpm -ql lipstick-jolla-home-qt5 for example. Usually files are well-named and well-organized, so you can find right file with no problem.