...

Be aware that it is not always clear which aspects of interoperability fall under the specification writers responsibility, and which fall under the implementation developers responsibility. Too often interoperability problems arise when each party is over-reliant on the other party to ensure interoperability.

Requirements

This paragraph should be moved to the requirements documentation.

Interop1 - Transparency in exporting of local data

Verify that it is visible for the user which locally edited data will be shared.
This includes explicitly visualising any removal of central data.

Interop2 - Transparency in importing of central data

Verify that it is visible for the user which displayed data comes from the shared central source.
This includes explicitly visualising any removal of local data.

Interop3 - Exhaustive data mapping

Verify that all the data from the central source is visible for the user.