Waitopedia is a comprehensive resource of information about SQL Server waits.
The description shown below is the top answer as voted by the Spotlight community.
The charts are based on 2.1 TB of data collected from 4207 instances uploaded by 323 Spotlight users over an 8 week period.
XE_TIMER_TASK_DONE
Category: Idle
SQL Server versions: 2008, 2008 R2, 2012, 2014, 2016, 2017
This is an idle wait and so it can be safely ignored.
What is XE_TIMER_TASK_DONE?
This wait has never occurred recently
XE_TIMER_TASK_DONE has not occurred recently on 4207 instances checked.