Oh! Now the button is there! I'm on the dev channel and downloaded today's image. Maybe the bug fairy saw this post and fixed it last night.
It looks like it has hung trying to import the two images in my gallery. I will log that bug if it doesn't finish.
I have a Nexus 7 2013 Flo (WiFi). I installed UT yesterday. This morning I switched over to the Dev version (2019-12-22).
When I open the camera app, the system hangs for a bit, then the tablet reboots. It did this when I was on the Stable version, too. It's not a reported bug on GitHub. Anyone know how to troubleshoot this?