wp-includes/PHPMailer/PHPMailer.php:2766Apply word wrapping to the message body.
public function setWordWrap() { if ($this->WordWrap < 1) { return; } switch ($this->message_type) { case 'alt': case 'alt_inline': case 'alt_attach': case 'alt_inline_attach': $this->AltBody = $this->wrapText($this->AltBody, $this->WordWrap); break; default: $this->Body = $this->wrapText($this->Body, $this->WordWrap); break; } }Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/PHPMailer/PHPMailer.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.