Development tools for Zephyr on STM32Workbench for Zephyr: VS Code extension to set up, build, flash and debug Zephyr applications on STM32.Devicetree manager: browse, edit and visualize Zephyr devicetree, STM32CubeMX-like for Zephyr.
It was too long ago, I don't remember.
In some programming/debug settings look for and use “Manual spec” (ST-LinkV2 and SWD) .
But now I use Atollic True Studio, STM bought it and it's free.