This feature: You can now see and action subtasks directly from your Project task list! - #26 by Adrienne_McCue
We relied on this for merging with an updated template, so that at least later subtasks in a task would be renewed. It seems missing now. Only tasks are shown in the list view and cannot be expanded.
The reason this is insufficient is that expanding subtasks before meant that I could multiselect to do bulk operations on subtasks. This doesn’t seem possible from the sidebar—you can multiselect, but I’m not sure why, because there’s no UI to do bulk operations. (If you right-click on the left-hand grippers on a subtask after multiselecting, it cancels your multiselection.)