As discussed on today's Cabal, the current process for testing w/ devfile v2 won't work as devfile doesn't support Theia vscode extensions.
Instead we need to rely on a .vscode/extensions.json or a .che/che-theia-plugins.yaml in the project's git repository.
Florent's blog shows how to do this.
See https://che.eclipseprojects.io/2021/06/23/@florent.benoit-devfile-v2-and-ide-plug-ins.html
For Che and Dev Spaces, we should document a KI that devfile v2 does NOT support inclusion of ide plugins, where this was possible in devfile v1 spec, and link to the doc about how to use a .vscode/extensions.json or a .che/che-theia-plugins.yaml files to specify IDE plugins: