Author: Shamim Rezaie
MDL-62231 block_recent_activity: Implement null provider for the block
http://git.moodle.org/gw?p=moodle.git;a=commit;h=1de2a1598ed0ea44f706adc83c83e7044c52a321
http://github.com/moodle/moodle/commit/1de2a1598ed0ea44f706adc83c83e7044c52a321
+ 3.5 en [privacy:metadata,block_recent_activity]