Why it matters
Lighthouse insights point at specific causes (unused JS, render-blocking requests, image delivery, third parties).
How to fix it
Open the Lighthouse audit named in the evidence and apply its recommendation.
More performance rules
void perf reports 25 rules in this category. Core Web Vitals and bytes: LCP, CLS, TBT, TTFB, JavaScript, CSS, fonts, images, caching and compression, measured as the median of several runs on a throttled mobile and a desktop profile.
images-missing-dimensionsImages without width/height or aspect-ratiorender-blockingRender-blocking resources delay first paintno-text-compressionText resources are served uncompressedcache-headersHashed static assets are not cached long-termthird-party-heavyHeavy third-party footprintdom-sizeDOM is very largebfcache-blockedPage is not eligible for the back/forward cachelighthouse-score-lowLighthouse performance score is low