Comment by Lerc

In general the absence of any clear statement of the source having an ability to know the information.

Specifically, yes The WSJ journal "sources familiar with" has been the end point of research into many claims that I have tried to find the origin of.

A lot of stories report that the WSJ has reported...

The combination of the paywall limiting casual readers to check the context of a reference and the perception that a widely reported claim is true needs a stronger foundation than 'A source familiar with said [something that is frequently an interpretation rather than a direct observation]

So yes, I'm definitely prepared to accept independent sourcing. Do you have a link?