The best-known article of the NATO charter is article 5 that defines that an attack on any NATO country should be considered an attack on all of them. But article 6 sets some geographic limitations that unfortunately might be relevant today:
For the purpose of Article 5, an armed attack on one or more of the Parties is deemed to include an armed attack:
- on the territory of any of the Parties in Europe or North America, on the Algerian Departments of France, on the territory of Turkey or on the Islands under the jurisdiction of any of the Parties in the North Atlantic area north of the Tropic of Cancer;
- on the forces, vessels, or aircraft of any of the Parties, when in or over these territories or any other area in Europe in which occupation forces of any of the Parties were stationed on the date when the Treaty entered into force or the Mediterranean Sea or the North Atlantic area north of the Tropic of Cancer.
The NATO countries themselves are the clear part, but the "any other area in Europe in which occupation forces of any of the Parties were stationed on the date when the Treaty entered into force" is a bit more difficult. I assume this is about Germany directly after the second world war, but I'm not sure if there might not be other cases where this clause applied.
Are there any other territories this clause would apply to that are still relevant today? Or is this clause essentially obsolete today as no such area exists anymore?