Controlled Frame API, restricted to Isolated Web Apps (IWAs), allows embedding all content, even third party content that can't be embedded in <iframe>. Controlled Frame also allows controlling embedded content with a collection of API methods and events, similar to WebViews on other platforms.
There was no newsletter for M139, since no Fugu and PWA features shipped in that milestone.
Please reach out with any questions, comments or suggestions.
Ajay Rahatekar and the Fugu team.