The glyph element in MathML 1 and 2 was intended to access special symbols from non-standard fonts that do not correspond to Unicode code points.

MathML 1和2中的glyph元素旨在访问来自不对应于Unicode代码点的非标准字体的特殊符号。

youdao

Since machines understand text as a series of numbers, which users see on screen as letters or characters, they developed a standard called Unicode that assigns a unique code to every glyph, character or letter in the world's written languages.

CNN: COMMUNICATION