A retailer losing conversions to invisible weight
Consumer Electronics Retailer, 2020. GTmetrix fully loaded time went from 37.3 seconds to 1.5 seconds, a 96% reduction. Requests dropped from 227 to 33; 194 removed. Page size fell from 4.98 MB to 847 KB. GTmetrix PageSpeed and YSlow scores (2020 scoring) moved from D and E to A and A. One before-and-after report pair; the report copy on file has the date, region, and browser redacted.
Years of app installs had layered JavaScript on top of JavaScript. Some of those apps were gone. The scripts weren't.