Author: Yuliya Bozhko
MDL-39207 badges: Generate badge assertions using user's backpack email if it is set
http://git.moodle.org/gw?p=moodle.git;a=commit;h=7e06ea6ab414f20729f5ad6513e42a78e7468b25
http://github.com/moodle/moodle/commit/7e06ea6ab414f20729f5ad6513e42a78e7468b25
+ 2.5 en [backpackemail_help,core_badges]