[happytoexplain]

> The ascent is the distance from the baseline to the top of the tallest glyph, so typically 1em. The descent is the distance from the baseline to the lowest point in any glyph. The descent can be different because on web fonts, glyphs like g or p can have tails that extend below the baseline.

Huh? Different from what? It's described as exactly the same thing as the ascent, but down. And why does the author specify web fonts? This sounds like it applies to fonts in general.

Edit: I think the author is just trying to say the descent varies across fonts, even measured in em. I think "web fonts" and "glyphs can have tails" are just red herrings.