I discovered a new feature in Firefox today. Fumbling with the keys, I must have accidentally pressed Ctrl-Shift-E, which brings up a box showing thumbnails of all the open tabs. This is a pleasingly visual way of getting an overview of what is shown on each separate tab. It took me a few more minutes to figure out what I had done but I managed to track it down on a list of keyboard shortcuts and have been able to add this new trick to my Firefox vocabulary.
I am, of course, mainly posting this for my own benefit. If I can remember to use it a few times over the coming week, it should become firmly established in my repertoire rather than getting forgotten.