To get list of event receiver attached to list /Library use followingpowershell script:
Add-PSSnapin microsoft.sharepoint.powershell -ErrorAction SilentlyContinue
$list.EventReceivers | Select Name, Assembly, Type
Recently I was working on sending mail using smtp server where I stuck on below error: IIS/SMTP - emails are stuck in mailroot/Queue ...
you will see this error when you try to add SharePoint Hosted app : Sorry, apps are turned off. If you know who runs the server, tell them...