Linux Mint team forks Nautilus
Apparently not content with the recent design changes to GNOME's Nautilus file manager, which removed functionality that some users deemed important, the Linux Mint team has forked the file manager to create Nemo.
The latest 3.5.x branch of Nautilus sports redesigned tool and menu bars but has also removed the dual pane, compact and sidebar views, the Go menu, and other features. Nemo currently includes very few visible changes from the 3.4.x branch of Nautilus, and the Linux Mint project has not yet officially announced what its plans for the new file manager entail, but it seems clear that its creation was prompted by the recent changes to Nautilus.
After creating its own GNOME Shell and Mutter forks, Nautilus is the third major component of the GNOME desktop stack that the Linux Mint team has decided to fork and maintain itself. Nor is Nemo the only fork of the GNOME file manager; the Elementary project also maintains its own derivative of Nautilus.
For those who wish to experiment with Nemo, the Linux Mint forums include instructions how to compile and install the file manager. However, users should be aware that the software is in very early stages and should not be used on production systems.