How can I modify the click event of the download button?

[andyxiong11]

I need to modify the response event for clicking the download button to customize the download method. Please tell me where it is located in the viewer.js file

[nicolo-ribaudo]

pdf.js/web/app.js

Line 1921 in 97c7a8e

eventBus._on("download", this.downloadOrSave.bind(this), opts);