Rawstudio is licensed under the GNU General Public License, version 2. This means you are free to download, use and modify the program under the conditions described in the license.
Source files for all releases can be found here.
Packages for Ubuntu can be found here.
There is a daily subversion checkout as tar.gz archive here.
Daily build packages for Ubuntu can be found here.
$ tar xfz rawstudio-x.y.tar.gz
$ cd rawstudio-x.y
$ ./configure
$ make
$ sudo make install
Anonymous checkout of active development tree is possible here.
$ svn co https://rawstudio.org/svn/rawstudio/trunk/ rawstudio # or branches/vX.Y/
$ cd rawstudio
$ ./autogen.sh
$ make
$ sudo make install