diff --git a/ArduinoCore-Linux/cores/arduino/Arduino.cpp b/ArduinoCore-Linux/cores/arduino/Arduino.cpp
index 6873ed2..ad09528 100644
--- a/ArduinoCore-Linux/cores/arduino/Arduino.cpp
+++ b/ArduinoCore-Linux/cores/arduino/Arduino.cpp
@@ -232,3 +232,5 @@ void analogWriteResolution(uint8_t bits) {
  * @note This is used to prevent watchdog timer resets in long-running loops
  */
 void yield() {}
+
+const String emptyString;
diff --git a/ArduinoCore-Linux/cores/arduino/Arduino.h b/ArduinoCore-Linux/cores/arduino/Arduino.h
index b8e1ead..020fea1 100644
--- a/ArduinoCore-Linux/cores/arduino/Arduino.h
+++ b/ArduinoCore-Linux/cores/arduino/Arduino.h
@@ -49,4 +49,8 @@ using namespace arduino;
 
 // supported by some platforms
 void analogWriteFrequency(pin_size_t pin, uint32_t freq);
-void analogWriteResolution(uint8_t bits);
\ No newline at end of file
+void analogWriteResolution(uint8_t bits);
+
+// ESP32-ism that is adopted by most Arduino implementations
+// and used by, at least, ESPAsyncWebServer
+extern const String emptyString;