Detect a website's tech stack — frameworks, CMS, e-commerce, analytics, tag managers, CDN, web server, language — from response headers, cookies, <meta generator> and HTML/script markers. HEURISTIC, signature-based on PUBLIC fingerprints (NOT the licensed Wappalyzer database): strong on popular tech, conservative elsewhere; not-listed ≠ absent. Each hit carries a confidence and the matched evidence. The URL is SSRF-checked; the fetch is capped.