Visual Studio Code – These two strings are supposed to be the same length but when printed they do not appear that way

I was guessing that one of the chars in a is strange. We can see this if we print them:

In [4]: for i, char in enumerate(a):
   ...:     print((i, char))
   ...:
(0, '|')
(1, ':')
(2, 'w')
(3, 'a')
(4, 't')
(5, 'c')
(6, 'h')
(7, ':')
(8, '️')
(9, ' ')
(10, ':')
(11, 'm')
(12, 'o')
(13, 'b')
(14, 'i')
(15, 'l')
(16, 'e')
(17, ' ')
(18, 'p')
(19, 'h')
(20, 'o')
(21, 'n')
(22, 'e')
(23, ':')
(24, ' ')
(25, ':')
(26, 'm')
(27, 'o')
(28, 'b')
(29, 'i')
(30, 'l')
(31, 'e')
(32, ' ')
(33, 'p')
(34, 'h')
(35, 'o')
(36, 'n')
(37, 'e')
(38, ' ')
(39, 'w')
(40, 'i')
(41, 't')
(42, 'h')
(43, ' ')
(44, 'a')
(45, 'r')
(46, 'r')
(47, 'o')
(48, 'w')
(49, ':')
(50, ' ')
(51, ':')
(52, 'l')
(53, 'a')
(54, 'p')
(55, 't')
(56, 'o')
(57, 'p')
(58, ':')
(59, ' ')
(60, ':')
(61, 'k')
(62, 'e')
(63, 'y')
(64, 'b')
(65, 'o')
(66, 'a')
(67, 'r')
(68, 'd')
(69, ':')
(70, ' ')
(71, ':')
(72, 'd')
(73, 'e')
(74, 's')
(75, 'k')
(76, 't')
(77, 'o')
(78, 'p')
(79, ' ')
(80, 'c')
(81, 'o')
(82, 'm')
(83, 'p')
(84, 'u')
(85, 't')
(86, 'e')
(87, 'r')
(88, ':')
(89, ' ')
(90, ' ')
(91, ' ')
(92, ' ')
(93, ' ')
(94, ' ')
(95, ' ')
(96, ' ')
(97, '|')

So we can see that at index 8 there is some kind of "zero width" character.

We can inspect the char to find its codepoint:

In [5]: ord(a[8])
Out[5]: 65039

This appears to be Unicode "VARIATION SELECTOR-16": https://www.fileformat.info/info/unicode/char/fe0f/index.htm

Some kind of modifying character that has no printable representation of its own.