Here is how you can track file downloads in GA4 BigQuery:
By Tracking file downloads, you can determine the most downloaded files on your website.
A GA4 property provides built-in file download tracking via its ‘File downloads’ enhanced measurement feature:
The ‘file_download’ event.
Once you have enabled/setup file download tracking in your GA4 property, whenever a user downloads a file (by clicking on a link leading to a file) on your website, GA4 fires the ‘file_download’ event.
By default, GA4 fires the ‘file_download’ event for the downloaded files with one of the following file extensions:
.pdf, .xls, .xlsx, .doc, .docx, .txt, .rtf, .csv, .exe, .key, .pps, .ppt, .pptx, .7z, .pkg, .rar, .gz, .zip, .avi, .mov, .mp4, .mpe, .mpeg, .wmv, .mid, .midi, .mp3, .wav, .wma.
In other words, the file extensions that match the following regex will trigger the ‘file_download’ event: