What the rank checker does
It tells you where your domain sits in the organic results for a keyword, and which URL is ranking. The large number is the position. The chart lines up the scanned results. Your domain is marked in the table.
The snapshot is live and will not match your personal Google exactly. Google mixes location, language, device and history. The tool does not imitate that. If the domain is missing, it is outside the scanned range, which is not the same as zero traffic.