Allow .gpx file type

Hello @webnewbie123456,

DCO Comment Attachment uses the standard WordPress media library. Therefore, if you want to modify something with the file upload rules, you need to work with it.

Is there a way to allow .gpx file types to be attached to comments?

Try WP Add Mime Types or File Upload Types by WPForms or analogs.
After adding a new file type, you may need to check it in the DCO Comment Attachment settings.

also can attached files be stored in a specific place

I don’t know the solution. Try WordPress Support Forums.

Marking as resolved. Feel free to reopen this topic, or create a new one if you have another questions.