Translations:Handbook:Parts/Working/Portage/83/en

Software in the portage tree can reside in different branches. By default the system only accepts packages that Gentoo deems stable. Most new software titles, when committed, are added to the testing branch, meaning more testing needs to be done before it is marked as stable. Although the ebuilds for those software are in the portage tree, portage will not update them before they are placed in the stable branch.