All Drupal 7 versions seem to be for Drupal 6

All of the Drupal 7 versions of the module have .info files that say it's for Drupal 6. For example:

name = Backup and Migrate
description = "Backup or migrate the Drupal Database quickly and without unnecessary data."
core = 6.x

; Information added by drupal.org packaging script on 2012-05-07
version = "6.x-2.6"
core = "6.x"
project = "backup_migrate"
datestamp = "1336415451"