Citation panel (sources panel)

The citation panel is the visible surface where an answer engine shows its sources. Every grounded engine renders it differently: Perplexity uses numbered chips inline with the answer plus a Sources list; ChatGPT Search uses inline numbered footnotes plus a sidebar Sources list; Claude shows citations with source links and quotes, and Anthropic does not document a side panel; Gemini has a Sources button at the bottom of the answer, or inline links, that opens a right-side panel; Bing Copilot links the entire sentence or passage inline plus a full list of links; Google AI Overviews shows links within and beside the block, with a layout that varies by query and device. The engine profiles document each one, and say where a layout is unverified.

The panel matters because it is where a citation turns into a click, and where position within the panel affects how many clicks. A source cited inline in the first sentence of the answer plausibly gets more attention than one buried in a list at the bottom, though no engine publishes click data by position. This is the attribution-quality dimension: being cited is necessary, but where in the panel you appear, and whether the engine quotes you accurately, determines the actual value of the citation.

For measurement, the citation panel is what citation-tracking tools parse to compute citation share and share of voice. Because each engine renders the panel differently and changes it without notice, parsing it reliably is the hard engineering problem underneath every measurement vendor, and the reason cross-vendor numbers are not directly comparable.