$ koji build --help
Usage: lkoji build [options] <target> <srpm path or scm url>
First option is build target (don't confuse it with destination
tag (where build ends) or buildroot (from where dependencies
are installed).
List of all available targets can be acquired by "
'koji list-targets'. For further info about how tags, targets "
and buildroot interact, check the "
https://docs.pagure.org/koji/HOWTO/#package-organization
(Specify the --help global option for a list of other help options)
Options:

The first option is the build target, not to be confused with the destination
tag (where the build eventually lands) or build tag (where the buildroot
contents are pulled from).
You can list all available build targets using the 'koji list-targets'
command. More detail can be found in the documentation.
https://docs.pagure.org/koji/HOWTO/#package-organization