I’ve noticed that iframes in feeds get stripped of most of their attributes.
Long been an issue with a feed I’ve written myself for the Star Citizen website. (/site/8562077)
I set the allowfullscreen=“true” attribute on all Youtube embeds so it’ll be possible to enter fullscreen from Newsblur, but this attribute is sadly stripped out.
More recently most of the iframes in the PC gamer feed (/site/8646949) end up pointing to about:blank. Looking at the actual feed data they don’t have a src attribute but both the attributes they have are stripped.
<iframe data-lazy-priority="low" data-lazy-src="https://www.youtube.com/embed/Cn7XLBykzEU" allowfullscreen></iframe>
These would obviously be useless without the javascript that is supposed to handle them, but maybe you could look for an attribute continuing “src” if no “src” is found? Alternatively leave the attributes in place so I can at least run some user javascript on them.
EDIT: Gamesradar (/site/6069094) has the same data-lazy-src attribute leading to blank iframes instead of Youtube embeds.