To build:
git clone https://github.com/counter185/voidsprite
cd voidsprite
cd freesprite/linux/flatpack
flatpak-builder --repo flatpak-repo .flatpak-builder com.github.counter185.voidsprite.yml --force-clean
flatpak build-bundle flatpak-repo voidsprite.flatpak com.github.counter185.voidsprite
This will produce a flatpak bundle: voidsprite.flatpak
. Install the resulting file with flatpak install ./voidsprite.flatpak
.