Why is OpenJDK 10 packaged as openjdk-11-*?

While looking to compile OpenJDK from source, the newest General Availability version (OpenJDK 10.0.1) insists on OpenJDK 9 or 10. JDK 11, however, is not due to be released until September 2018.

However, to my surprise, when I do apt search openjdk the result is:

openjdk-11-jdk - OpenJDK Development Kit (JDK)
openjdk-8-jdk - OpenJDK Development Kit (JDK)

No OpenJDK 9 or 10!

And wait, is that OpenJDK 11? Maybe a Beta release? Nooo….

So I looked at apt show openjdk-11-jdk:

Package: openjdk-11-jdk
Version: 10.0.1+10-3ubuntu1

Why has OpenJDK 10 been packaged as openjdk-11-*??

Can I run a packaged Chrome app as a tab in the browser?

I use a few packaged Chrome apps, namely Wunderlist for Chrome, Text, and Google Keep.

Packaged apps launch a new window when you click on their icon on the New Tab page:

animated screenshot showing packaged app behavior

I keep a Chrome window maximized on a second monitor at all times. I want to keep window switching on this monitor to a minimum, and the fact that these apps require spawning a new window is rather frustrating.

Is there any way to launch these packaged Chrome apps in a tab instead of a new window?