for over 10 years now Apple has stated it won't implement Customized Built In Elements ( "is" extends ) If you want to dive in deep: https://stackoverflow.com/

for over 10 years now Apple has stated it won't implement Customized Built In Elements ( "is" extends ) If you want to dive in deep: https://stackoverflow.com/search?q=liskov https://stackoverflow.com/search?q=liskov Here is Apple debating all non Liskov believers: https://lists.w3.org/Archives/Public/public-webapps/2013OctDec/0801.html https://lists.w3.org/Archives/Public/public-webapps/2013OctD... *going back over 10 years to 2013, Who said Web Components was a fad*