In F39, none of these packages show up under dnf [install, search, provides]. What are their new names?

Kickstart files for other spins, e.g. Fedora Electronics Lab, can be found in /usr/share/spin-kickstarts/ after installing the spin-kickstarts package. These pre-made configuration files can be a great place to start, as they already have some useful pre and post-installation scripts.

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You can create a customized kickstart file by running system-config-kickstart.

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You might have to install the package first with dnf install system-config-kickstart