<script src='...' checksum='2fd4e1c67a2d28fced849ee1bb76e7391b93eb12' />
Which would allow the browser to use cached copies of files even if from different domains. Not sure where I saw that.
That attribute is meant to verify resource contents. The strategy of using it as a cache ID is still being discussed, but last I looked into it, there were some cache poisoning concerns.
You might find this thread useful: https://news.ycombinator.com/item?id=10311020
<script src='...' checksum='2fd4e1c67a2d28fced849ee1bb76e7391b93eb12' />
Which would allow the browser to use cached copies of files even if from different domains. Not sure where I saw that.