https://www.quaxio.com/unicode_superscript.html

Unicode(*) superscript 

Unicode has superscript versions of numerical characters. These are
however not always rendered correctly (e.g. they are currently broken
on MacOSX and iOS with the default font). The reason is because the
superscript character 1-3 are defined in separate code blocks from
characters 0, 4-9. On Apple products, the default font has
superscript characters 1-3 but falls back to a different font for the
other numbers.

A simple fix would be for Apple to add the other superscript
characters to the default font (or remove 1-3 and fallback for all
superscript characters, but that might break software which doesn't
implemenent font fallback).

This is a test page. You can compare how your browser renders with
the default font vs screenshots of what I'm getting.

Some superscript numbers don't line up:

Your browser: x0, x1, x2, x3, x4, x5, x6, x7, x8, x9.

Screenshot of mine: [unicode_su]

As a result, some of the following lines look like x^(ab), others
look like x^a^b, and others just look broken.

Your browser:

x00, x01, x02, x03, x04, x05, x06, x07, x08, x09

x10, x11, x12, x13, x14, x15, x16, x17, x18, x19

x20, x21, x22, x23, x24, x25, x26, x27, x28, x29

x30, x31, x32, x33, x34, x35, x36, x37, x38, x39

x40, x41, x42, x43, x44, x45, x46, x47, x48, x49

x50, x51, x52, x53, x54, x55, x56, x57, x58, x59

x60, x61, x62, x63, x64, x65, x66, x67, x68, x69

x70, x71, x72, x73, x74, x75, x76, x77, x78, x79

x80, x81, x82, x83, x84, x85, x86, x87, x88, x89

x90, x91, x92, x93, x94, x95, x96, x97, x98, x99

Screenshot of mine:

[unicode_su]

Why do I care? Some Wikipedia pages use numerical superscript
characters and can lead to mistakes!

Credits

Thanks to @FakeUnicode and @AlecMuffett for helping figure out what's
going on!

Footnote

* Unicode is working as designed here. It's unfortunate that related
characters are in separate blocks since fonts are typically designed
to cover specific set of blocks. A font can cherry-pick characters
from any block.