https://code.visualstudio.com/docs/editor/extension-gallery#_command-line-extension-management
code --extensions-dir <dir>
Set the root path for extensions.
code --list-extensions
List the installed extensions.
code --show-versions
Show versions of installed extensions, when using --list-extension.
code --install-extension (<extension-id> | <extension-vsix-path>)
Installs an extension.
code --uninstall-extension (<extension-id> | <extension-vsix-path>)
Uninstalls an extension.
code --enable-proposed-api (<extension-id>)
Enables proposed API features for extensions. Can receive one or more extension IDs to enable individually.