This library is part of the AppImage project. It implements functionality for dealing with AppImage files. It is written in C++ and is using Boost.
As a user, you normally do not need to deal with this library. Tools that use it (like the optional appimaged daemon) usually come with a bundled copy of it.
If for some reason you need to do a local development build, on a deb-based system (tested on Ubuntu xenial) do:
sudo apt-get -y install automake cmake libtool libcairo-dev libfuse-dev git
git clone https://github.com/AppImage/libappimage
cd ./libappimage/
mkdir build
cmake .. -DBUILD_TESTING:bool=False
make
sudo make install
cd ..
Your contributions are welcome.
If you make or suggest changes to this code, please test that the resulting executables (like the appimaged daemon) are still working properly.
If you have questions, AppImage developers are on #AppImage on irc.freenode.net.