Kiwi-related tasks (createKiwiImage, kiwiBuild, etc?) are not listed in the Method dropdown of the Tasks page. I think they just need to be listed here: https://pagure.io/koji/blob/master/f/www/kojiweb/index.py#_488
createKiwiImage
kiwiBuild
As it is a plugin, you've to add it explicitely to Tasks in web.conf.
Tasks
web.conf
Metadata Update from @tkopecek: - Custom field Size adjusted to None
https://pagure.io/koji/blob/master/f/www/conf/web.conf#_47
Oh, I would have expected the plugin to expose it's tasks automatically or something. Sorry for the noise!
Metadata Update from @alexi: - Issue close_status updated to: Invalid - Issue status updated to: Closed (was: Open)
Problem is, that plugin is on the hub and web don't know about these. We should do something about this (and also web plugins) but it is low priority.
This issue has been migrated to Fedora Forge: https://forge.fedoraproject.org/koji/koji/issues/3501
Please continue any further discussion there.