In the Contributors page you have listed all the users assigned to the projects hosted on your account/organization and to the localization projects you're an admin of, along with their email address.

If you want to export a list of the contributors assigned to a project who were active in a particular period, you can do this in the Stats page, in Stats by contributors. Clicking the download button next to the date range picker, you will get a file with containing the contributor names, emails and contributions in the selected interval.

You can also get a list of the contributors assigned to a localization project using the API, with the help of the contributors/list method.