v1.7.3
We additionally provide immutable tarball:
https://github.com/saitoha/libsixel/releases/download/v1.7.3/libsixel-1.7.3.tar.gz
According to Issue #64, GitHub auto-generated tarball(https://github.com/saitoha/libsixel/archive/v1.7.3.tar.gz) may be not immutable.