vingtetun/pdf.js — comment on commit 08af0c7686bc2ca5b0648196e5b8887c93ae78d2
File: extensions/chrome/manifest.json line 7
By benadida:

I don't think you need the permissions to http://*/*.pdf at this stage, because you're not page-mod'ing those URLs. The webRequest API is contained in the experimental permission, I believe.