How does UTF8 work, anyway?

utf8.txt

The following is the Black Female Astronaut emoji as encoded
in UTF8, shown in hex:

F0 9F 91 A9 F0 9F 8F BF E2 80 8D F0 9F 9A 80   byte value
 1  2  3  4  5  6  7  8  9  0  1  2  3  4  5   byte number

As you can tell it's fifteen bytes. If you express the hex
digits in binary you can see how UTF8 encoding works, and
you can see it's made up of four characters.

F0 9F 91 A9   F0 9F 8F BF   E2 80 8D     F0 9F 9A 80 
11110000      |             |             |
10011111      |             |             |
10010001      |             |             |
10101001      |             |             |
              11110000      |             |
              10011111      |             |
              10001111      |             |
              10111111      |             |
                            11100010      |
                            10000000      |
                            10001101      |
                                          11110000
                                          10011111
                                          10011010
                                          10000000

For every multi-byte UTF8 character, the leading 1-bits of
the first byte tell you how many total bytes the character
spans. The nul-byte and the 127 characters of the original
7-bit ASCII set take up one byte.

All single-byte UTF8 characters have a 0 for the first bit.

These are the fileformat.info pages for the four characters
shown above:

http://www.fileformat.info/info/unicode/char/1f469/index.htm
http://www.fileformat.info/info/unicode/char/1f3ff/index.htm
http://www.fileformat.info/info/unicode/char/200d/index.htm
http://www.fileformat.info/info/unicode/char/1f680/index.htm

That's woman, modifier-fitzpatrick-type-6*, joiner, rocket.

Fitzpatrick Type, you say?
https://en.wikipedia.org/wiki/Fitzpatrick_scale

👩🏿‍🚀