Developer credits
Git commits in Moodle 3.3.3 by Mark Johnson
commit 8edb87a37f486710a36684aecf4c8c27c89741b4 Author: Mark Johnson <mark.johnson@open.ac.uk> Date: Thu, 26 Oct 2017 21:59:35 +0800 Tag: v3.3.3 MDL-60600 core_output: Clear static icon system cache between unit tests