Authorization required: sitemap.xml
Verification word: duo

Approve on your phone -- open or scan this on a device with your passkey:
  https://auth.ck1.me/a/eyJhbGciOiJIUzI1NiJ9.eyJyZXMiOnsidHlwZSI6Im9iamVjdCIsImlkIjoic2l0ZW1hcC54bWwifSwid29yZCI6ImR1byIsImp0aSI6IjU3M2M5YmViMDg4NzRkMTQ5MTI1N2RlZjA5NTE1OTVmIiwiaXNzIjoic2VydmVzLmNrMS5tZSIsImF1ZCI6ImF1dGguY2sxLm1lIiwiaWF0IjoxNzgyNzA4OTA2LCJleHAiOjE3ODI3MDkyMDZ9.c7t2X9wsOnskszSD1_D1mebMw4jGGXB28L_jZJJrZv4

(No browser on this box? Cmd-click that link to open it on your laptop;
 it shows a QR you can scan with your phone.)

Then fetch the file -- this command waits until you approve:
  curl -fL 'https://serves.ck1.me/sitemap.xml?grant=eyJhbGciOiJIUzI1NiJ9.eyJyZXMiOnsidHlwZSI6Im9iamVjdCIsImlkIjoic2l0ZW1hcC54bWwifSwid29yZCI6ImR1byIsImp0aSI6IjU3M2M5YmViMDg4NzRkMTQ5MTI1N2RlZjA5NTE1OTVmIiwiaXNzIjoic2VydmVzLmNrMS5tZSIsImF1ZCI6ImF1dGguY2sxLm1lIiwiaWF0IjoxNzgyNzA4OTA2LCJleHAiOjE3ODI3MDkyMDZ9.c7t2X9wsOnskszSD1_D1mebMw4jGGXB28L_jZJJrZv4' -o 'sitemap.xml'