When a tool installer plugin is installed after a Jenkins restart — either due to a user clicking "Download now and install after restart" in the plugin manager, or because they manually placed the .jpi file in the plugins directory — the tool installer JSON file is currently not downloaded.

Therefore the user must wait up to 24 hours for the tool installer data to be downloaded by Jenkins, or manually navigate to Manage Plugins > Advanced > Check Now.

Ideally Jenkins would download missing tool installer data as soon as possible after such a plugin is loaded into Jenkins.