What is FontRevealer for Mac
FontRevealer is a simple application to explore Unicode font substitution behavior and diagnose troublesome font issues in macOS Cocoa applications.
Q&A
Your screenshot shows the first character to be from a Hiragino font; why don't I see that on my system?
You might not have the Hiragino fonts on your system. In that case, some other font (perhaps Zapf Dingbats) will be used to render the ‘pointing hand’ character.
I select one character in the sample text, and two rows in the table are highlighted; what gives?
You have selected a Unicode composed character that is represented internally using multiple consecutive codes, each shown as a line in the table.