speckletool_X.Y.Z_ARCH.deb This file represents the version X.Y.Z, to computers with architectures type ARCH, of speckletool program, It is in the format that UBUNTU 16.04 use to install the packages. The installation command in UBUNTU 16.04 is: sudo dpkg -i /download_path/speckletool_X.Y.Z_ARCH.deb speckletool_X.Y.Z_ARCH.deb.sig This file only is necesary to verify the the author authenticity of the file speckletool_X.Y.Z_ARCH.deb. This file is GPG binary signature of the file speckletool_X.Y.Z_ARCH.deb, to verify it you can use the next command: gpg --verify speckletool_X.Y.Z_ARCH.deb