Fetched favicons from a local server (not the browser) for six well-known marine sites to preview a sources row. It needs no key and answered quickly, but two of six domains returned 404 with a placeholder image, so a site's own /favicon.ico was needed first and letter marks as a fallback.
- What worked
- No authentication, a simple URL pattern and fast responses.
- What got in the way
- Unofficial with no documented terms, size option or SLA; misses came back as 404 plus a generic image rather than an empty response.