Let's see what this breaks...

src/input/kbMatrixImpl.h

@@ -0,0 +1,19 @@
+#pragma once
+#include "kbMatrixBase.h"
+#include "main.h"
+
+/**
+ * @brief The idea behind this class to have static methods for the event handlers.
+ *      Check attachInterrupt() at RotaryEncoderInteruptBase.cpp
+ *      Technically you can have as many rotary encoders hardver attached
+ *      to your device as you wish, but you always need to have separate event
+ *      handlers, thus you need to have a RotaryEncoderInterrupt implementation.
+ */
+class KbMatrixImpl : public KbMatrixBase
+{
+  public:
+    KbMatrixImpl();
+    void init();
+};
+
+extern KbMatrixImpl *kbMatrixImpl;