Ebuilds may have a Gentoo revision number associated with them. This is a -rX suffix, where X is an integer see . This component must only be used for Gentoo changes, not upstream releases. By default, -r0 is implied and should not be specified manually.

Ebuilds should have their -rX incremented whenever a change is made which will make a substantial difference to what gets installed by the package by substantial, we generally mean "something for which many users would want to upgrade". This is usually for bugfixes.

Simple compile fixes do not warrant a revision bump; this is because they do not affect the installed package for users who already managed to compile it. Small documentation fixes are also usually not grounds for a new revision.

When doing a revision bump, the usual rules about dropping to ~arch apply. See .