Minimizes Main-Thread Work

Your browser's renderer process translates your HTML, CSS, JavaScript and other code into the web page where users interact with it. The main thread of that process handles the most code. It executes the work of the HTML, builds the DOM, and administers much of the functions of the CSS and JavaScript.

How to reduce main-thread load

Some of the steps Google suggests to reduce these sizes and times include:

• Use code splitting to isolate the code that users need specifically
• Minify, compress and remove unused code
• Cache requests so that the page limits network trips on repeat visits. Using a PRPL Pattern can help here.