It looks like LXRandr can save configurations.
But where are they saved and in what form?
(I was thinking about activating them by shortkey.)
To know what has changed in the home folder:
find ~/ -mmin -5 -type f
You can change 5 to a smaller number if you wish.
In this way, after saving configuration in LXRandr and running this command, the last change recorded is in
~/.config/autostart/lxrandr-autostart.desktop. That's it.
To open that:
It contains something like:
[Desktop Entry] Type=Application Name=LXRandR autostart Comment=Start xrandr with settings done in LXRandR Exec=xrandr --output LVDS --mode 1680x1050 --rate 60.1 --output VGA-0 --off OnlyShowIn=LXDE
It says that it just starts "xrandr with settings done in LXRandR". It's an
xrandr configuration. In the example the external display is connected by VGA but shut down.
(To activate that configuration by a keybind, the line to be used is the one after
Exec=. It will vary according to the active display settings at the moment when LXRandr saved them. Many separate configurations can be saved in this way to be used with different keybinds; but after saving with LXRandr the file
lxrandr-autostart.desktop is overwritten.)