Shared caches stopped working years back, to close a security hole. They're redownloaded per domain now. https://dev.to/rstacruz/public-cdns-arent-useful-anymore-2b6...
There’s a proposal to bring back cross-site file caching with a fix for the privacy issue:
https://github.com/WICG/cross-origin-storage
There’s a proposal to bring back cross-site file caching with a fix for the privacy issue:
https://github.com/WICG/cross-origin-storage