Last year, I answered [Wayback/Archive] javascript – Bookmarklet to append a string to a URL – Stack Overflow (asked by [Wayback/Archive] Karlo Guidoni Martins, thanks!).
It is about not being able to run bookmarklets on pages hosted by for instance:
gist.githubusercontent.comraw.githubusercontent.com
GitHub is an exception, as RAW files from these services do work fine:
At first sight, when running a Bookmarklet on those RAW GitHub served pages, you do not see an error: it just looks like the Bookmarklet does not work at all. The last part is right, but in the Chrome console you can actually see the error.
That error lead me to my answer:
The Wiert Corner - irregular stream of stuff 