This is currently only a draft/proof of concept. The plugin has only test action inside, only the class
DrawIoLocalStorageExample does something relevant!
When starting DrawIoLocalStorageExample it is a simple java programm and can be started
directly. It loads a changed variant of
https://github.com/jgraph/drawio-integration/blob/master/localstorage-svg.html
with some additional hooks inside.
SWT browser will open changed file. You can edit and do drawio stuff. Then doing a "save" will store data in localstorage - additionally xml message content will be shown in Java System out by callback…