Take a look at uBlock's "local mirroring"

[ghostwords]

https://github.com/gorhill/uBlock/wiki/Experimental-features#privacy-exposure-reduction-local-mirroring

Look for "local mirroring" here: https://github.com/gorhill/uBlock/releases

https://github.com/gorhill/uBlock/search?q=local+mirroring&type=Issues&utf8=%E2%9C%93

[fixanoid]

Couldn't find anything similar last night and I remember we spoke about something like this a little while ago. I like the name: local mirroring is probably a better way of explaining what this is supposed to do. I'll review uBlocks implementation, but from the brief reading, the main difference is most likely going to be gorhill's CDN replacement vs all replacement for known and common scripts that will be in this database. Also, I think a separate extension is probably a better idea than throwing everything into a an existing blocker.