Suppose I have the following two-leg flight:

• From: Outside EU and Schengen.
• To: Outside EU and Schengen.
• Same airline for both legs.
• Connection airport: In continental Europe, inside EU and Schengen.

Suppose also that I can enter the state where the airport is located (either I have a visa for it I don't need a visa with my passport).

During my connection, will I be allowed to leave the transit area? The terminal overall?

If the answer is "only in some EU states" - please explain why some allow it and some don't. Same if the answer is "only in some airports, but it's not uniform even within the same state".

_{The question generalizes this one about Helsinki. It's also inspired by and related to this question of mine.}

Suppose I have the following two-leg flight:

• From: Outside the EU and Schengen.
• To: Outside the EU and Schengen.
• Same airline for both legs.
• Connection airport: In continental Europe, inside the EU and Schengen.

Suppose also that I can enter the state where the airport is located (either I have a visa for it or I don't need a visa with my passport).

During my connection, will I be allowed to leave the transit area? The terminal overall?

If the answer is "only in some EU states", please explain why some allow it and some don't. Same if the answer is "only in some airports, but it's not uniform even within the same state".

_{The question generalizes this one about Helsinki. It's also inspired by and related to this question of mine.}