So I used Master Controller to export the town's genealogy. I wondered what it would look like, since of course it couldn't look like any version of a family tree..

I didn't expect it to be incomprehensible!

When I copy the text into Libre Office there are 222 pages. Part of that is that every line consists of either 1 or 2 and one or two words, and almost every other line is just the word "even." I think I understand what's going on there. "Even" is a placeholder to make an empty line between category lines. And most of the lines make sense, they are "Type" (example Surname, skill, trait, etc) and "Note" (the values that go with those categories.

It gets more exciting between sims. I think this is where the relationship information is but I don't understand how it works. What do these types of lines mean? And how do I use them to construct a family tree?

1 FAMS @F10@
0@1147@INDI

There's been a lot of Story Progression Chaos since I started this world, and it was shipped with a shocking number of pregnancies in the first place, and the Stories only tell you who's paying or not paying child support, not which children they're supporting or not supporting.

MC's Export Geneology functions aren't meant to provide output that is readable by us. They provide files in GEDCOM format for importing into a third party program/website service that can read the data and produce family trees out of it. The most famous such site is probably Ancestry.com, but most of them use this file format. I'm not sure what is most commonly used by players who wish to work with their TS3 data that way, although MC's FAQ on the subject suggests Family Echo.

Thank you! I'm a wee bit disappointed that I have to do another step, but that's okay.

That was painless! I found a couple surprises that actually please me very much. And it's really pleasing to have it laid out so nicely.