Doesn't work on Firefox 57 - Content Security Policy (CSP) blocks the script

[fed-franz]

I didn't try with previous versions, but on FF57, the script seems to be blocked:

Content Security Policy: The page’s settings blocked the loading of a resource at self (“script-src https://assets-cdn.github.com”).

I suppose this is related to some Firefox settings, but in any case, it prevents the script from working.

[FarhadG]

Interesting! It must be some sort of FF setting. Lets see if someone is interested in solving this...

[JustAnotherUser19401]

Could be caused by an ad blocker if you have one installed.

[fed-franz]

No it's not.
I've just tried again with a new profile, with no addons, and still the same error.
FF is now at version 61. I tried on both Ubuntu16 and Windows10