@beardalaxy It's up to the application to save and restore it's location. Same's true on Windows. Windows Librewolf requires me to manually resize and move it so I can get two windows side by side on one screen each boot

@beardalaxy The kernel, Linux doesn't handle windowing, so why do you expect it to do that?

Good thing Xorg, Wayland and decent DE's and WM's are free software and you can add such functionality or pay someone else to add it.