SQL Azure – is master billable?

In SQL Azure, when you create a “server”, a master database is automatically created and you’ll see it listed in the databases list.  Here’s a screenshot after I created a new database called Test.

I was surprised that master is listed like a standard 1GB database and I feared that it might be billable.  I could not find any information so this morning, after a day of usage, I went into my billings.

Looks like only my Test database was counted as billable.

[Edit]: Got confirmation from MS that the master database is not billable.