@michelin good memory (I forgot or never knew). https://lwn.net/Articles/512166/ https://lwn.net/Articles/960630/
Finding this was worthwhile for the title "Oracle: SELECT * FROM Sun" (not a hit for this topic) of https://lwn.net/Articles/329223/ which also then reminds me of the somewhat similar situation with the Java TCK.
Now I'm idly curious about other [historic or current] open source with proprietary tests case studies. I haven't verified these but candidates include Android, Elastic, MongoDB, RHEL.