The KJV variants are based on the Byzantine manuscripts. (KJV, MKJV, NKJV, etc..)
Most of the others are written from the Alexandrian manuscripts which are older and closer to Jerusalem.

Mark 1:2
(AMPC) Just as it is written in the prophet Isaiah: Behold, I send My messenger before Your face, who will make ready Your way--[Mal_3:1]
(AMPC+) N1Just as it is written in the prophet Isaiah: Behold, I send My messenger before Your face, who will make ready Your way--[Mal_3:1]
(ASV) Even as it is written in Isaiah the prophet, Behold, I send my messenger before thy face, Who shall prepare thy way;
(BSB) As it is written in Isaiah the prophet: “Behold, I will send My messenger ahead of You, who will prepare Your way.”
(CSB) As it is written in Isaiah the prophet: See, I am sending my messenger ahead of you; he will prepare your way.
(ESV) As it is written in Isaiah the prophet, “Behold, I send my messenger before your face, who will prepare your way,
(ESV+) R2As it is written in Isaiah the prophet,N1 R3“Behold, I send my messenger before your face, who will prepare your way,
(GNB) It began as the prophet Isaiah had written: "God said, 'I will send my messenger ahead of you to open the way for you.'
(GW) The prophet Isaiah wrote, “I am sending my messenger ahead of you to prepare the way for you.”
(HCSB) As it is written in Isaiah the prophet: Look, I am sending My messenger ahead of You, who will prepare Your way.
(JUB) as it is written in the prophets, Behold, I send my messenger before thy face, who shall prepare thy way before thee.
(KJV) As it is written in the prophets, Behold, I send my messenger before thy face, which shall prepare thy way before thee.
(KJV+) AsG5613 it is writtenG1125 inG1722 theG3588 prophets,G4396 Behold,G2400 IG1473 sendG649 myG3450 messengerG32 beforeG4253 thyG4675 face,G4383 whichG3739 shall prepareG2680 thyG4675 wayG3598 beforeG1715 thee.G4675
(MKJV) as it is written in the Prophets, "Behold, I send My messenger before Your face, who shall prepare Your way before You.
(MSG) following to the letter the scroll of the prophet Isaiah. Watch closely: I'm sending my preacher ahead of you; He'll make the road smooth for you.
(NAS77) As it is written in Isaiah the prophet, "BEHOLD, I SEND MY MESSENGER BEFORE YOUR FACE, WHO WILL PREPARE YOUR WAY;
(NAS95) As it is written in Isaiah the prophet: "BEHOLD, I SEND MY MESSENGER AHEAD OF YOU, WHO WILL PREPARE YOUR WAY;
(NAS95+) R1As it is writtenG1125 in IsaiahG2268 the prophetG4396: "R2BEHOLDG2400, I SENDG649 MY MESSENGERG32a N1AHEADG4253 OF YOU, WHOG3739 WILL PREPAREG2680 YOUR WAYG3598;
(NIrV) Long ago Isaiah the prophet wrote, "I will send my messenger ahead of you. He will prepare your way." (Malachi 3:1)
(NIV) as it is written in Isaiah the prophet: "I will send my messenger ahead of you, who will prepare your way"—
(NKJV) As it is written in the Prophets: "BEHOLD, I SEND MY MESSENGER BEFORE YOUR FACE, WHO WILL PREPARE YOUR WAY BEFORE YOU."
(NLT) just as the prophet Isaiah had written: “Look, I am sending my messenger ahead of you, and he will prepare your way.


Let's compare these to the original Greek.

(Greek NT INT+)
καθως
G2531
ADV
καθώς
just as
να
ως
G5613
ADV
ὡς
which how
τσβ
γεγραπται
G1125
V-RPI-3S
γράφω
to grave
εν
G1722
PREP
ἔν
in
τω
G3588
T-DSM
ὁ
the
να
ησαια
G2268
N-DSM
Ἡσαίας
Hesaias
να
τω
G3588
T-DSM
ὁ
the
να
προφητη
G4396
N-DSM
προφήτης
a foreteller
να
τοις
G3588
T-DPM
ὁ
the
τσβ

προφηταις
G4396
N-DPM
προφήτης
a foreteller
τσβ
ιδου
G2400
V-2AAM-2S
ἰδού
lo!
εγω
G1473
P-1NS
ἐγώ
I
τσβ
αποστελλω
G649
V-PAI-1S
ἀποστέλλω
set apart
τον
G3588
T-ASM
ὁ
the
αγγελον
G32
N-ASM
ἄγγελος
a messenger
μου
G3450
P-1GS
ἐγώ
of me
προ
G4253
PREP
πρό
fore
προσωπου
G4383
N-GSN
πρόσωπον
the front

σου
G4675
P-2GS
σύ
of thee
ος
G3739
R-NSM
ὅς
who, which
κατασκευασει
G2680
V-FAI-3S
κατασκευάζω
to prepare thoroughly
την
G3588
T-ASF
ὁ
the
οδον
G3598
N-ASF
ὁδός
a road
σου
G4675
P-2GS
σύ
of thee
τσβ
εμπροσθεν
G1715
PREP
ἔμπροσθεν
in front of
τσβ
σου
G4675
P-2GS
σύ
of thee

(Greek NT BYZ+) ωςG5613 ADV γεγραπταιG1125 V-RPI-3S ενG1722 PREP τοιςG3588 T-DPM προφηταιςG4396 N-DPM ιδουG3708 V-2AAM-2S εγωG1473 P-1NS αποστελλωG649 V-PAI-1S τονG3588 T-ASM αγγελονG32 N-ASM μουG1473 P-1GS προG4253 PREP προσωπουG4383 N-GSN σουG4771 P-2GS οςG3739 R-NSM κατασκευασειG2680 V-FAI-3S τηνG3588 T-ASF οδονG3598 N-ASF σουG4771 P-2GS εμπροσθενG1715 PREP σουG4771 P-2GS

The KJV uses the Byzantine manuscripts.

G4396
προφήτης
prophētēs
prof-ay'-tace
From a compound of G4253 and G5346; a foreteller (“prophet”); by analogy an inspired speaker; by extension a poet: - prophet.
Total KJV occurrences: 149

B-A-C said:

Let's compare these to the original Greek.

Click to expand...

I am afraid this means nothing to me I dont read Greek

Always be careful in what people say about this issue , there is a whole lot missing in other bibles, the other bibles tend to go with the texts that came from Alexandria Egypt, one of them in the Vaticannus, the KJV goes with the textus receptus, and the Masoretic text, and if you want a good testimony of how someone did research, and used to be for the new bibles but then through research changed his mind, there is David W Daniels.

Gerbolski said:

Always be careful in what people say about this issue , there is a whole lot missing in other bibles, the other bibles tend to go with the texts that came from Alexandria Egypt, one of them in the Vaticannus, the KJV goes with the textus receptus, and the Masoretic text, and if you want a good testimony of how someone did research, and used to be for the new bibles but then through research changed his mind, there is David W Daniels.

Click to expand...

Yes the Alexandrian texts (Sinaiticus, Vaticanus, Alexandrinus) came out of Alexandria Egypt and was a Gnostic epicenter. There is evidence of Gnostic doctrine motivating some of the textual changes.

I found it interesting that one of the textual critics Hort explained the shorter verses in the Alexandrian stream by two councils around 300AD where the church leaders inserted words and verses. There was no historical basis or evidence. One of his committee members came to denounce Hort and his methods