From time to time it might happen to be forced to run a non-notarised application on your Mac. In recent years this has become more and more difficult. Starting with an optional setting in Mac OS X Leopard, by default there are only 2 settings left since macOS 15 Sequoia: App Store only or App Store and other notarised apps.
The following command restores the Mac OS X Leopard behaviour and allows globally for opening arbitrary apps. Danger: this reduces data security and integrity and should be used only if absolutely unavoidable with apps from trusted sources.
sudo spctl --global-disable
and type your password. Then open the Privacy & Security control panel of System Settings, scroll down to Allow Applications From and choose the now new item Anywhere from the popup menu. Identify yourself as administrator again and give explicit permission.