What is a BuildRoot Override
Sometimes a package you are trying to build can't be done until another package that it depends on is updated. When building packages for rawhide, successful builds become available fairly soon after they complete. These packages can then be used to build other packages against.
However, when building for any of the release branches below rawhide, builds are usually only available to be built against once they are pushed to "stable". Often it isn't practical or convenient to wait for this to happen. You can work around this problem by submitting a BuildRoot Override for any package builds you need that haven't yet made it to "stable". This will place the package into the BuildRoot for the branch that you specify until the expiry date that you specify. During this time, the package is available to be built against. It is good practice to specify an expiry date that is only as long as you need (eg, a few days). It can easily be extended if needed. You can also manually expire the Override before the expiry date. Note that there is only one builroot per stable branch, so your override applies to everyone's package builds, so take care if this will affect others.
To submit a BuildRoot override for a package, you need to be a member of the packager group.
It usually takes about 15 to 30 minutes for a new BuildRoot Override to take effect.
Using fedpkg to manage koji BuildRoot Overrides
As of version 1.34 of fedpkg you can make and manage overrides via 'fedpkg override'. Run 'fedpkg override --help' for full information.
Using Bodhi to manage Koji Buildroot Overrides
See bodhi's https://bodhi.fedoraproject.org/docs/user/buildroot_overrides.html or 'man bodhi' and look for the OVERRIDES section.