fill-rule

A typical SVG renderer doesn't actually render text directly to the canvas, like a GUI library would, but rather converts it into paths and then renders them. After all, a text in SVG is basically a fancy way to define paths.

The edge case that arises when treating text as paths are that it must not be affected by the fill-rule property. It might not affect a typical Latin text, but in complex scripts, it might lead to bugs like this:

A proper parser must always set text fill-rule to nonzero.

And before you think that no one would make such an obvious mistake, the image above was produced by Inkscape 1.2 (2022).