Magento compiles numerous scripts into a small number of JavaScript bundles when bundling is enabled. The Magento website then downloads these bundles for each page. In this case, browsers carry out the downloading in sync. Magento pauses page rendering while bundles are downloading until they are all finished. The best element of bundling is that we could choose where to load a given bundle. For instance, we want to bundle everything relevant to checkout and just load it on the checkout page.