Niq Dudfield

 Seems like there's a few issues that have accreted as this feature doesn't see much use (particularly from primary maintainer)

Long excised

https://dxr.mozilla.org/mozilla-release/source/toolkit/components/reader/Readability.js#625 https://www.ctrl.blog/entry/browser-reading-mode-content.html

More generally: > If there is an error though — it should be persistent or least visible for a while…

https://developer.apple.com/forums/thread/94567 

Was able to build the extension by creating a new extension and manually adding in the files to the Resources It seems there are some issues with `frameId` missing, which...

  *Seemingly* works if default frameId to `0`

Asked about content scripts iframes on Apple developer forum here: https://developer.apple.com/forums/thread/653307

Updated question

 > I see. The frameId missing issue has been fixed. It should be in the next seed, and also Safari Technology Preview. Posted 16 hours ago by timothy.hatcher 