“You can learn a lot about a site when you monitor its network connections when you connect your browser to it.
“You may see connections to third-party sites, ads, web analytics scripts and a lot more just from that.
“A common practice is to use popular JavaScript libraries or frameworks like jQuery or Ember. Sites may load locally hosted versions of those, or versions hosted by public content deliver networks (CDN) such as those by Google, Microsoft or Cloudflare.
“These resources are often essential for a site’s functionality, and blocking them may break part or all of a site.
“There are two concerns that Internet users may have when it comes to the use of these content delivery networks: privacy and speed.
“Speed is easier to explain. While it is often faster to use a CDN for resources than a locally hosted version on the site’s server itself, it still means having to make a connection to the CDN in first place. That’s not as fast as making these resources available locally on the user’s computer. …”
Source: gHacks Tech News
Decentraleyes for Firefox loads CDN resources locally
