Author: Matthew Noorenberghe
MDL-41634 - URL Download Repository doesn't warn when asked to download non-image files
http://git.moodle.org/gw?p=moodle.git;a=commit;h=d64a0e917308bfc358b0c1cdfebd7b33ba34574d
http://github.com/moodle/moodle/commit/d64a0e917308bfc358b0c1cdfebd7b33ba34574d
+ 2.4 en [validfiletype,repository_url]