Why was https://english.stackexchange.com/q/524832 migrated from Law? An ordinary anglophone wouldn't know the legal meaning. Sven Yargs hints to it
https://english.stackexchange.com/questions/524832/what-does-extended-mIn legal documents, and elsewhere, "extended" can mean (among other things) "expanded in force or reach" or "prolonged in time." Without additional context, I don't think it's possible to discern which of these meanings (if either) the authors of the Treaty of Lisbon Protocol intended in this instance.