Never-Slow Mode a.k.a. Slightly-Fast Mode

For these sites, the browser imposes per-interaction resource limits, giving users a better user experience, potentially at the cost of extra developer work. The following policy logs errors to the same endpoint but does not modify content:

The heart of NSM is a set of policies derived from experience analysing hundreds of sites. In practical terms, this means that sites should attempt to host as many of their resources as possible from a single origin and explicitly budget connections for third parties.

Source: github.com