Ah, I was under the impression Google and Apple had created their own separate apps and these third-party apps merely worked on the same principle. It's interes

Ah, I was under the impression Google and Apple had created their own separate apps and these third-party apps merely worked on the same principle. It's interesting that the document you linked indicates the interoperability between different countries' apps was down to an EU-wide standard. I guess this meant the apps of different EU countries were compatible but only with each other.