To give a little more detail, logged http (not https) into en: on one page,
and am showing the "Login successful" page.
Then, bring up a de: page in a second window -- the de: page has
Anmelden / Benutzerkonto erstellen
I've made a picture of the cookies. Note that I get cookies for an awful
lot of related sites, even though I've started with no cookies, and have
not accessed them.