The @babel/plugin-syntax-do-expressions package enables Babel to parse the ECMAScript "do expressions" proposal. This allows developers to use do expressions, which are blocks that evaluate to the last expression within them. Adding this plugin to your Babel configuration allows the compiler to understand and process this experimental syntax, paving the way for utilizing do expressions in your JavaScript code before they are formally standardized. It's a syntax-only plugin; you'll need a transform plugin for full functionality.