Cookies are created on the client side to persist some setups like the chosen locale or the bundle sort order. These cookies are session cookies (removed when the browser is closed) attached to the root of the URL space, thus globally visible.
There has been a fix in
FELIX-3236 to persist the locale cookie for twenty years. Still the cookie is attached to URL root space.
Propose to addition of a global setCookie(name, value) method to the support.js script, which sets a cookie to a given name and value and defaults the expiry to twenty years and attaches the cookie to the root of the web console (appRoot, /system/console by default).