src/vs/workbench/contrib/terminal/browser/environmentVariableInfo.ts/mutatorTypeLabel
function mutatorTypeLabel(type: EnvironmentVariableMutatorType, value: string, variable: string): string {
	switch (type) {
		case EnvironmentVariableMutatorType.Prepend: return `${variable}=${value}\${env:${variable}}`;
		case EnvironmentVariableMutatorType.Append: return `${variable}=\${env:${variable}}${value}`;
		default: return `${variable}=${value}`;
	}
}