Is there a “glyph not found” character?

Question

Let\'s assume we have a text that contains a Unicode character that cannot be displayed because our font has no corresponding glyph. Usually, a placeholder is displayed inst

Answer 1

No, there is no “glyph not found” character. Different programs use different graphic presentations. An empty narrow rectangle is a common rendering, but not the only one. It could also be a rectangle with a question mark in it or with the code number of the character, in hexadecimal, in it.

So it is better to e.g. display a small image of the character along with the character itself, so that the reader can compare them.