There you go conflating forward voltage and applied voltage again.
It would have been nice, after doing all that cutting and pasting, had you learned something in the process. How about some of your "applied physics". Definitions are useless if you cannot apply them to Vf of an LED.
This thread began with you saying "Current will ALWAYS be regulated by varying the output voltage"
At issue here is whether, as you say, an LED's forward voltage is a source of an electromotive force or, as I say, is an electric potential difference.
There is a distinct disparity between an electromotive force and a electric potential difference.
In the US "voltage "is the common term for the SI quantity of "electric potential difference".
You referred to Vf as if it were the origin of the electromotive force. It is a difference in electric potential between the LED's anode and cathode which is created by current flowing through a resistive conductor (LED). The origin electromotive force of the forward voltage's electric potential difference is the driver's Input voltage.
The origin of an electromotive force is typically a battery or magnetic flux.
An electromotive force is measured in volts, but is NOT a voltage (electric potential difference )
Electric potential difference is measured in volts and is also known as voltage.
An electromotive force CAN create a current IF connected to a conductor.
When current flows through a resistive conductor it creates an electric potential difference.
The origin electromotive force driving the LEDs is the driver's
Input Voltage.
The LED in this case is the resistive conductor NOT the electromotive force.
When DC current flows through a resistive conductor it creates an electric potential difference between the anode and cathode, commonly referred to as forward voltage (Vf).
The amount of potential difference is a function of the current flowing through the LED's resistance.
The LED's Vf is NOT an electromotive force, it is an electric potential difference.
Still stand by: "Current will ALWAYS be regulated by varying the output voltage"