contextValue 
  Context value of the resource group. This can be used to contribute resource group specific actions. For example, if a resource group is given a context value of exportable, when contributing actions to scm/resourceGroup/context using menus extension point, you can specify context value for key scmResourceGroupState in when expressions, like scmResourceGroupState == exportable.
"contributes": {
  "menus": {
    "scm/resourceGroup/context": [
      {
        "command": "extension.export",
        "when": "scmResourceGroupState == exportable"
      }
    ]
  }
}Content copied to clipboard
This will show action extension.export only for resource groups with contextValue equal to exportable.