It seems to me that they are using Rollup to bundle the PDF.js source code into their own. I’d guess it makes sense for PDF.js since you likely won’t need it o

It seems to me that they are using Rollup to bundle the PDF.js source code into their own. I’d guess it makes sense for PDF.js since you likely won’t need it outside of this library in your own project and it comes with multiple builds, of which they might choose one specific. Then install speeds are faster and node_modules are smaller.