how do I find it?
Since your source is task scheduler, try this.
($env:PSModulePath -split ';' | get-childitem -recurse | where-object -property fullname -match TaskScheduler).fullname
My source is "scheduledtasks",so I get this:
PS C:\> ($env:PSModulePath -split ';' | get-childitem -recurse | where-object -property fullname -match scheduledtasks).fullname
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\ScheduledTasks
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\ScheduledTasks\en-US
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\ScheduledTasks\MSFT_ScheduledTask.format.ps1xml
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\ScheduledTasks\MSFT_ScheduledTask.types.ps1xml
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\ScheduledTasks\MSFT_ScheduledTask_v1.0.cdxml
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\ScheduledTasks\PS_ClusteredScheduledTask_v1.0.cdxml
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\ScheduledTasks\PS_ScheduledTask.types.ps1xml
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\ScheduledTasks\PS_ScheduledTask_v1.0.cdxml
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\ScheduledTasks\ScheduledTasks.psd1
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\ScheduledTasks\ScheduledTasks_5378ee8e-e349-49bb-83b9-f3d9c396c0a6_HelpInfo.xml
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\ScheduledTasks\en-US\MSFT_ScheduledTask_v1.0.cdxml-help.xml
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\ScheduledTasks\en-US\PSScheduledJob.dll-help.xml
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\ScheduledTasks\en-US\PSScheduledJobPrxy.psm1-help.xml
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\ScheduledTasks\en-US\PS_ClusteredScheduledTask_v1.0.cdxml-help.xml
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\ScheduledTasks\en-US\PS_ScheduledTask_v1.0.cdxml-help.xml
PS C:\>
Might be something you loaded in your Documents subfolder.
PS C:\> $env:PSModulePath -split ';'
C:\Users\Dave\Documents\WindowsPowerShell\Modules
C:\Program Files\WindowsPowerShell\Modules
C:\WINDOWS\system32\WindowsPowerShell\v1.0\Modules\
C:\Program Files\Microsoft Message Analyzer\PowerShell\