Backport is licensed under the MIT License, which is an open-source initiative approved license.
Under this license, you may use Backport for any purpose you wish WITHOUT ANY WARRANTY, and modify it as you see fit -- subject to the one condition:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the software
In non legal terms, this means that whenever an application built with Backport is distributed -- either as source code, or as a binary package, the license text must also accompany the distribution in some form. This may be in the form of a printed documentation, a digital list of credits distributed with the application, or even as acknowledgement from within the application itself (e.g. in credits, 'about', etc).
Similarly, if the the Backport project is used as the basis to a new library or distribution, attribution must be made for any substantially copied portions (algorithms, designs, etc.).
At no point is Backport or any of its contributors to be misrepresented as endorsing a project that uses this engine without prior written acknowledgement from the maintainers.