interop is a subset of tests chosen beforehand (nowadays, mostly by devs voting in the github issues). This says Safari has reached 100% on the subset of tests agreed upon for interop-25. Those specific tests can be expanded by clicking it in the menu. It'll take you here:

https://wpt.fyi/results/wasm/jsapi?label=experimental&label=...

The full test-suite of wasm tests are here:

https://wpt.fyi/results/wasm