Decentraleyes prevents loading common scripts from big name CDNs. Requesting a script from a google-owned CDN with your google cookies and the current URL as the referrer is a way to spy on you.
Decentraleyes loads these common scripts from it's own cache instead.
Thanks for the tip. From the localCDN description:
Differences between LocalCDN and Decentraleyes
LocalCDN contains a big collection of frameworks and useful functions.
New: Sync extension settings with Firefox Sync or own server
Includes Rocket Loader, Findify, Vue.js, page.js, lozad, AngularJS, Bootstrap, Google Material Icons, React, Vue, Chart.js and much more. The list will be continuously updated.
Includes Font Awesome in different version (v3.x, v4.x, v5.x, v6.x)
Prepared rules for uBlock Origin/uMatrix/AdGuard and notifications if rule changes are necessary
Removes integrity/crossorigin attributes to replace more frameworks
The source code is public ( https://codeberg.org/nobody/LocalCDN ) and it has a reasonable amount of stars. So I think it should be fine. No guarantees, though.