Gentoo Linux is (not uniquely) a source-based distribution. This means that the package system contains just instruction files that describe how to download and install software. This file is called an ebuild file and, like the PKGBUILD file previously, contains information about metadata, dependencies, and build instructions. Unlike Arch Linux, this descriptor file is the complete distribution – packagers do not build a binary distribution package using the metadata file.

The process for submitting a new package to Gentoo Linux (once you have created the ebuild file) is described on their community documentation https://wiki.gentoo.org/wiki/Submitting_ebuilds. As with other distributions, you will need to become part of the development community to add the package yourself, but you may convince an existing developer to maintain the package for you.