Linus has released 5.6-rc1 and closed the
merge window for this development cycle. “This was actually a
slightly smaller merge window than usual, but I think that what happened is
simply that the holiday season impacted new development. It impacted the
5.5 rc series less than I had expected, but seems to instead have caused
5.6 to have slightly less development than normal.“

Source: LWN.net – Kernel prepatch 5.6-rc1