The participants table download in Moodle always included user emails, but should have only done so when users' emails are not hidden. Versions affected: 3.9 to 3.9.2, 3.8 to 3.8.5 and 3.7 to 3.7.8. This is fixed in moodle 3.9.3, 3.8.6, 3.7.9, and 3.10.