They pretty much intentionally lost S3TC patent case opting not to push for patent invalidation https://www.prnewswire.com/news-releases/itc-judge-rules-tha... The thing about s3tc is _its Apple own technology_, just renamed and repurposed.
https://en.wikipedia.org/wiki/S3_Texture_Compression "This mode operates similarly to mode 0xC0 of the original Apple Video codec." is an understatement. S3 directly lifted Apple patented QuickTime Road Pizza technique of encoding 4 colors using 2 values (same math, same values, same purpose, no prior art acknowledgment), to ~10 years later sue and win.