Mainstream Linux distributions are, in most cases, constructed from collections of binary (precompiled) packages in either RPM or deb format. RPM stands for Red Hat Package Manager and is used in Red Hat, Suse, Fedora, and other distributions based on them. Debian-derived distributions, including Ubuntu and Mint, use the Debian package manager format, deb. In addition, there is a light-weight format specific to embedded devices known as the Itsy PacKage format, or ipk, which is based on deb.
The ability to include a package manager on the device is one of the big differentiators between build systems. Once you have a package manager on the target device, you have an easy path to deploy new packages to it and to update existing ones. I will talk about the implications of this in the next chapter.