Keyframe.time

Description

The time of the keyframe.

In a 2D graph you could think of this as the x-value.

Additional resources: value.

using UnityEngine;

public class Example : MonoBehaviour
{
    void Start()
    {
        AnimationCurve curve = AnimationCurve.Linear(0, 0, 5, 5);
        // Extract the time from the first keyframe of a curve
        Debug.Log(curve[0].time);
    }
}