SF Symbols in Text

// How is it I can use SF Symbols images in text strings?

echo >bug.txt 􀌛
hexdump bug.txt
> f4 80 8c 9b 

f4 = 11110100
80 = 10000000
8c = 10001100
9b = 10011011

First byte starts with 1111 which means it's 
a 4 byte value. 

Wikipedia explains how to decode this:
https://en.wikipedia.org/wiki/UTF-8

100000000001100011011 = 0x10031B

0x100000-0x10FFFF is "Supplementary Private Use Area-B"

// Gist of a small Swift script that prints all the characters in the
// private use block.
https://gist.github.com/fdstevex/5412fad1d205e8b00ad6288e0769389b

#!/bin/swift 
import Cocoa
for ch:UInt32 in 0x100000..<0x10FFFF {
    let arr = [ch]
    let array: [UInt32] = [CFSwapInt32(ch)]
    let data = array.withUnsafeBytes { (ptr) -> Data in
        return Data(ptr)
    }
    if let str = String(data: data, encoding: .utf32) {
        print("\(String(format: "%08X", ch)): \(str)")
    }
}

0010074A: 􀝊
0010074B: 􀝋
0010074C: 􀝌
0010074D: 􀝍
0010074E: 􀝎
0010074F: 􀝏