Ah, yes, Elon, thank you for informing me that Charlie said that you suck. It was about time for me to realize that Charlie is an incessant critic who deserves to be terminated immediately without prior notice or discussion. CHARLIE, COME HERE. *gunshots sound*
1 - jwt is the authentication cookie u get when u sign in with ur password, ur browser stores the jwt and then any further interaction authenticates using it
2 - yes, userscripts, extensions, custom frontends, apps, all apps have access to jwt