Developer credits
Git commits in Moodle 3.5.3 by Guillermo Alvarez
commit 5b75de57f203a31d6527b6da4e0c8d32bbe33b90 Author: Guillermo Alvarez <guillermo.alvarez@blackboard.com> Date: Sat, 25 Aug 2018 01:40:06 +0800 Tag: v3.5.3 MDL-63231 filepicker: Skype validation for null values