Google Explains 503s, Robots.txt Limits & Bracket URLs – SEO Pulse via @sejournal, @MattGSouthern

Google's reminder to use 503 status codes during PHP patch downtime, alongside new guidance on robots.txt limits, bracket‑URL handling, and JPEG XL support in Images and Discover, signals tighter control over how sites signal temporary outages and crawl permissions. For website owners, the 503 recommendation means that any scheduled maintenance—especially PHP updates that temporarily disable dynamic pages—should return a proper 503 response with a Retry‑After header. This prevents Googlebot from indexing error pages and preserves ranking equity. The clarified robots.txt limits (maximum 2 KB and 10 kB per rule) force owners to audit oversized disallow/allow files, while bracketed URLs (e.g., example.com/page[1]) now require explicit allowance to avoid accidental blocking. JPEG XL adoption in Google Images also means that serving this format can boost visibility in Discover, but only if crawlers can access the files without restriction. **Actionable tips:** 1. Implement server‑side logic that detects maintenance windows and automatically serves a 503 with a Retry‑After header; test with curl to confirm correct response. 2. Audit your llms.txt and robots.txt files using llmscentral.com’s validator to ensure they stay under Google’s size caps and explicitly allow bracketed URL patterns. 3. Register JPEG XL images in your sitemap and verify crawlability in Google Search Console, adjusting llms.txt entries if necessary to prevent accidental blocking.