Sources

Annotations · Sources (breadcrumb Data / Sources; opened from the Sources card on Data, 02 ③; no sidebar item, the sidebar keeps Data highlighted): third-party data vendors only. Sources only feed the library (02); nothing reads them directly. Binance, Alpaca, Tradier and other brokers or exchanges are not listed: they supply data with the keys of their account in Accounts (06) and appear directly in the Add data source list (02b); the subtitle says so and links Accounts (06). ① + Add source adds a data vendor (dialog 02e). Vendors are data-only and never trade. ② Credentials: API key •••• 3f9a (last 4 characters). Vendors not added yet are greyed: Polygon Not added · Add source (opens 02e with Polygon selected). ③ Supports: asset classes the vendor can deliver (Crypto, Equity, Option); Add data (02b) only offers these. ④ Last test: result of the last Test connection (one read-only quote request). ⑤ Row ⋮ menu (open on MarketData.app): Test connection, Edit (API key), Remove (only when no dataset uses it as Source; otherwise blocked with the datasets listed).
Sample data: vendors and keys are for illustration only.