How to use this feature
To use Request Blocking in DevTools:
- Right click on a resource in the Network Panel.
- Select Block request URL - this resource is now excluded from subsequent page loads.
When to use this feature
I made a video lesson part of my DevTools course on this topic, specifically, how blocking a resource can help quantify how "expensive" such a resource is on page performance. If you have access to the course, check out Lesson #7 Script Execution Cost.