LV 1.2.5 — Core Web Vitals

REQ-1.2.5-CWV

Proof level: TECHNICAL POC

Demonstrates

• ✓ responsive WebP photos (480-1920px, srcset, fetchpriority) cut the mobile LCP in a lab run (4x CPU, ~1.6 Mbit/s, 150 ms) from ~7.5 s to ~1.3 s and the transfer from ~1.3 MB to ~0.34 MB on the demo host; CLS ~0.00

Pending external information

• ○ Measured with a custom lab script, not yet Lighthouse CI - LCP/CLS/INP budgets in CI (docs/performance.md) are still to be automated; field data (CrUX) cannot exist before go-live

View live demonstration →

Technical documentation

• docs/performance.md

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