Ubuntu is planning to develop its own file manager which will be introduced with their QT5 powered Unity8 desktop environment from Ubuntu 14.10 onwards. Ubuntu is currently using Nautilus File manager (also known as 'Files'), developed by GNOME developers.Ubuntu users & developers are growing increasingly unhappy with the direction at which Nautilus file manager is leading. There are many necessary features which are missing in latest Nautilus, forcing users to replace Nautilus with their favourite file manager like feature-rich nautilus fork, Nemo or the popular Thunar - which is inarguably one of the best file managers.
Ubuntu developer Oliver Grawert is currently seeking help from community and asking for feedback of features which users & developers would like to see.
(GNOME's Nautilus File Manager)
"With all the complaints and unhappiness about Nautilus upstream ripping out things like dual pane and other beloved and helpful features I expect we can do better and I think this is the right time to:
a) collect requirements
b) file wish list bugs
c) if *you* want to contribute, get in contact with the developers(CCed)
The new core apps are all 100% developed by the community under guidance of the canonical design team." quoted Oliver Grawert in his mailing list post.
Canonical is planning convergence using Mir display server from Ubuntu 14.10 onwards, which means that new file manager which Ubuntu developers are planning to introduce will be available for all platforms like Smartphones, Tablets, Desktops & Netbooks. Currently, no other information regarding upcoming Ubuntu's home grown file manager is released. Only time will tell whether Ubuntu will fork nautilus file manager & add new features like they usually do with all GNOME based applications, or team will develop entire file manager from scratch. More detailed information regarding this is likely to be available soon.
Source : Ubuntu Archives