Constant EXTENSION_TYPE_SYSTEM 

const EXTENSION_TYPE_SYSTEM: u8 = 0;

VS Code’s ExtensionType enum - mirror the numeric values used by the renderer’s getInstalled(type?) IPC so the filter in GetInstalledArgs matches what the channel client sends.

src/vs/platform/extensions/common/extensions.ts in the pinned VS Code dependency:

export const enum ExtensionType { System = 0, User = 1 }