By the end of the merge window, 12,632 non-merge changesets had been
pulled into the mainline repository for the 5.5 release. This is thus a
busy development cycle — just like the cycles that preceded it. Just over
half of those changesets were pulled after the writing of our first 5.5 merge-window summary. As is
often the case later in the merge window, many of those changes were
relatively boring fixes. There were still a number of interesting changes,
though; read on for a summary of what happened in the second half of this
merge window.

Source: LWN.net – [$] The end of the 5.5 merge window