I develop an extension in Firefox 76.0.1 and add a content script via content_scripts in the manifest.js. I figured out that on some pages the script is not inserted into the page. For instance, https://support.mozilla.org/en-US/kb/address-bar-autocomplete-firefox
Here, no script is loaded at all.
Usually, it looks like this:
But on the mentioned pages it looks like this in the debugging tool:
I found this issue:
Stackoverflow: Firefox content script not loading in some pages, where the problem was a Content-Security-Policy in the header of the page.
But I don’t have such policy in my headers.
Does anybody has an idea what is wrong here?