What does the Windows flag in the Linux logo of kernel 3.11 mean?

A couple of years ago, Linus Torvalds was discussing Linux version numbers and said, "I think I will call it 3.11 Linux for Workgroups."

It turns out he wasn't joking. With a release candidate of Linux 3.11 now available, Torvalds has actually named the new version of the kernel "Linux for Workgroups." He even gave it a Windows-themed boot icon featuring Linux's mascot penguin, Tux, holding a flag emblazoned with an old Windows logo. The name "Linux for Workgroups" follows such whimsical past Linux version names as "Pink Farting Weasel," "Killer Bat of Doom," "Erotic Pickled Herring," and "Jeff Thinks I Should Change This, But To What?"

From the news: 20 years after Windows 3.11, Linus unveils “Linux for Workgroups”

It is because of the project name, "Linux for Workgroups", it is a reference for Windows 3.11 for Workgroups. I've found it quite interesting; I also found a reference here.

It's a joke by Linus. This page: http://www.extremetech.com/computing/161426-linux-3-11-named-linux-for-workgroups-in-odd-homage-to-its-archenemy-windows gives more detail.

Ever the prankster, Linus Torvalds has paid homage to Windows 3.11 by naming Linux 3.11 “Linux for Workgroups.” Tux, Linux’s penguin mascot that appears during boot-up, is now holding a Windows flag (pictured above). This might seem a little odd, given Linux’s reputation as the Windows antithesis, but Linux for Workgroups is actually one of Linux’s saner names. Over the years, the Linux kernel has been lumbered with some amazingly undignified designations, such as Unicycling Gorilla, Erotic Pickled Herring, and Holy Dancing Manatees, Batman!