Implement the XDG session management protocol, in order to allow clients to ask the compositor to save window state for them. This works via creating a xdg_session_v1 object...
Does it also restore the content of unsaved files of the application? If not, I'll prefer systemctl hibernate. I wonder, what this new feature is for. Gnome had it in the past, MacOS has it, but I don't see what the use case is.
Does it also restore the content of unsaved files of the application?
That's up to the application.
If not, I'll prefer systemctl hibernate. I wonder, what this new feature is for.
I believe this is for storing the position of specific windows, for multi-window applications (e.g. GIMP's multi-window mode). So hibernation is very unrelated.