Meaning
A question mark drawn in white or pale grey, often with an outline, the quieter twin of the red ❓. It still marks a question, just with less urgency.
It suits polite or gentle questions, menu-style FAQs and minimalist designs where red would feel too loud: “Anyone free for lunch tomorrow❔” On light backgrounds it can be hard to see, so the red version is safer when you want the question noticed.