From DDG: "We've noticed that removeAllUserScripts removes not only user scripts but also all web extensions, which was unexpected. It would be great to have a way to avoid this if possible." Scripts and stylesheets added for Safari's internal use for Web Extensions should not be exposed on the public objects and methods clients use on the WKUserContentController. We should filter out user scripts and stylesheets owned by Web Extensions when we return the list of scripts and stylesheets. We should also not remove web extension scripts/stylesheets when client call removeAllUserScripts/removeAllUserStyleSheets.
<rdar://problem/114823215>