metamask-extension/shared/constants/desktop.ts

export const EXTENSION_ERROR_PAGE_TYPES = {
  NOT_FOUND: 'not-found',
  CONNECTION_LOST: 'connection-lost',
  DESKTOP_OUTDATED: 'desktop-outdated',
  EXTENSION_OUTDATED: 'extension-outdated',
  CRITICAL_ERROR: 'critical-error',
  ROUTE_NOT_FOUND: 'route-not-found',
  PAIRING_KEY_NOT_MATCH: 'pairing-key-not-match',
};