There are a lot of GPS traces on the website. I can download them from https://www.openstreetmap.org/traces, but how can I download these files in a specific region, for example download all GPX files in China?
Through the API. Note that you can download in bboxes only, not regions and that depending on the area this can be quite a time consuming undertaking.
JOSM can also download raw gps traces. Just click the checkbox in the download window.
Duplicate post: https://help.openstreetmap.org/questions/64942/how-can-i-download-gpx-files-in-a-region
Please don’t post your question in multiple forums at the same time. Thank you.