Author: Jake Dallimore
MDL-35290 files: File manager reports files which can't be read
http://git.moodle.org/gw?p=moodle.git;a=commit;h=67fa4b55b95ea179f68ae8f5f2af84adf18f5546
http://github.com/moodle/moodle/commit/67fa4b55b95ea179f68ae8f5f2af84adf18f5546
+ 3.3 en [storedfilecannotreadfile,core_error]