John 21 in the context of "Disciple whom Jesus loved"

The phrase "the disciple whom Jesus loved" (Ancient Greek: ὁ μαθητὴς ὃν ἠγάπα ὁ Ἰησοῦς, romanized: ho mathētēs hon ēgapā ho Iēsous) or, in John 20:2; "the other disciple whom Jesus loved" (τὸν ἄλλον μαθητὴν ὃν ἐφίλει ὁ Ἰησοῦς, ton allon mathētēn hon ephilei ho Iēsous), is used six times in the Gospel of John, but in no other New Testament accounts of Jesus. John 21:24 states that the Gospel of John is based on the written testimony of this disciple.

Since the end of the first century, the beloved disciple has often (but not unanimously) been identified with John the Evangelist. Scholars have debated the authorship of Johannine literature (the Gospel of John, Epistles of John, and the Book of Revelation) since at least the third century, but especially since the Enlightenment. The authorship of the Epistles by John the Apostle is rejected by many modern scholars, but not entirely. There is a consensus among Johannine scholars that the beloved disciple was a real historical person, but there is no consensus on who the beloved disciple was.