7.9.13 base.text.sub Superscript / Subscript
The <sup> element represents a superscript and the <sub> element
represents a subscript.
Example
Mlle Gwendoline wrote the equation
f(x, n) = log4xn.
Markup: base/text/text-sub.twig
<abbr>M<sup class="{{modifier_class}}">lle</sup></abbr> Gwendoline wrote the equation <code>f(x, n) = log<sub class="{{modifier_class}}">4</sub>x<sup class="{{modifier_class}}">n</sup></code>.
Source:
base/text/_text.scss, line 201