The ascent of a font is the distance between the font's baseline and the highest glyph point. There is no standard for how this supposed "highest glyph point" is determined, so there are different modes presented in Unity to choose from, each determining a different "highest glyph point". The Ascent Calculation Mode determines how the ascent will be calculated. There are three options for how this calculation will be chosen: Legacy version 2 mode (glyph bounding boxes), Face ascender metric, and Face bounding box metric. The method chosen may have affect the vertical alignment of the font.
Legacy version 2 mode (glyph bounding boxes) measures the ascent using the highest point reached by any one of the font's glyphs ...
