I've been searching everywhere for this and I can't find it anywhere. I'm learning how to develop WatchOS apps.
In the tutorial I'm working with they're working on building a Modular Large Complication.
I found that the Siri watch face supports Modular Small complications (the only watch face I could find supporting that).
Unfortunately after extensive searching I can't find a watch face on my Series 5 Apple Watch with Watch OS version 6.1 that supports a modular large complication.