metamask-extension/ui/app/helpers/constants/error-keys.js

export const INSUFFICIENT_FUNDS_ERROR_KEY = 'insufficientFunds';
export const GAS_LIMIT_TOO_LOW_ERROR_KEY = 'gasLimitTooLow';
export const TRANSACTION_ERROR_KEY = 'transactionError';
export const TRANSACTION_NO_CONTRACT_ERROR_KEY = 'transactionErrorNoContract';