when I change variables in the inspector, edit nodes in the scene or change anything in the editor, the variables are saved.
What I want is the same thing for my Editor pugin.
Is there a way to save these changes? I mean, under _enter_tree, I could load data from a save file, when the plugin starts up....
but instead of this, Id prefer not to have to create a file in my resources for this...

could I save a string or int somewhere in the scene? Or into the editor somwhere? it's really not much data, just to remember a few settings of my Editor plugin.
any suggestions?