I got to debug an existing #Ghidra extension from VSCode by:
- Copying .vscode/ template directory to the original (Eclipse-based) repo
- Fill in the path of my Ghidra installation in build.gradle (this can be pbbly done more elegantly by setting the env)
- Renaming the .classpath file produced by Eclipse, as it confuses VSCode
- Manually loading the plugin from Code Browser's File/Configure menu

The debugging experince is unfortunately shit so far, I can't even see which breakpoint is hit - I'll keep on reading VSCode tutorials...