Eensy is an open source project, comprised of many other open source projects, and you are welcome to contribute to it and make it better.

To build Eensy for a specific board from source, clone the projects, configure buildroot, and make.

git clone
git clone
cd buildroot
# where DEFCONFIG is one of the defconfig file names in eensy/configs/
# optionally configure more options as necessary
make menuconfig

For more detailed instructions and further information on using and configuring your Eensy install, see the documentation.