The user manual has the following shortcuts in the lighttable:
|z|fully zoom into the image while the key is pressed
|ctrl-z|fully zoom into the image and show areas in focus
Neither of these do anything. It doesn’t matter if I am in file manager mode or the zoomable light table. I just want to be able to scroll through the thumbnails and zoom in on any images I want to see full screen, then quickly get back to the zoom level I was before. What am I missing?
Unless you’re using an older version, try w to zoom and ctrl-w to zoom & show focus. The shortcuts changed a while back to allow ctrl-z to work for undo.
Another tip: hold down h for a list of shortcuts. I use that one all the time. 
Thanks, Steve! yes, that works. The online manual I was looking at must have ben for an older version. I did find the 3.0 manual and I’ll use that from now on!
Wow, that’s good to know. Now to see if I can remember this one useful tip!