Anyone know what the purpose of tagging a class with *[class]

Question

I received a file from a client today that is a template for an e-mail and in the css for the mobile version all of the class specifications were preceded with *[class]

Answer 1

There is a yahoo fix/bug workaround that uses this technique (css classes) in html email design. There was a bug where Yahoo rendered all media queries by default, and this was the common solution.

There have been reports that Yahoo fixed the bug recently.