Labels for the "highlighting a time region" 's shape

The highlighting time series regions with rectangle shapes was very helpful but it omited how to add labels for those highlight areas. What I would ideally like is something that looks like:

The only I could kind of get this to work was by adding a bar graph with one bar of height 0. This is hacky and causes a lot of functionalities to bug (e.g.: the viewport doesn’t get refitted properly when some of the graphs are hidden…).