I wonder if Ladybird has explored running these interop tests yet. Or maybe these are just a subset of WPT?
Here's a comparison including the big 3, ladybird, servo, and flow
https://wpt.fyi/results/?label=master&product=chrome&product...
To answer your question, yes. Apple requires 80% test passage of all the tests on web-platforms-test in order to be considered as a valid browser for iOS so they specifically targeted this suite to reach that milestone
It's a pretty silly requirement because wpt is not really meant to be representative of all web platform standards. It includes tests for non-standard features and the majority of tests are simple unicode glyph rendering tests.
They are indeed just a subset of WPT. Although the way subtests are weighted in the score calcustion is slightly different for the "interop" score.
You can edit the "products" represented in the table and add "Ladybird" to the list. [1]
Their result is: 1974740 / 2152733 (91%)
They also have their own dashboards tracking this [2]
[1] https://wpt.fyi/results/?product=ladybird
[2] https://grafana.app.ladybird.org/public-dashboards/2365098a1...