Don't forget to register for them in the [Events] section of your .HOOK file if you want to be notified of these events!
[Events]
ChannelAutoDownloadCompleted=1
ChannelAutoDownloadCleanup=1
[Config]
Url=... (URL of the downloaded file)
SaveFilename=... (where the file has been saved)
AutoDeleteTime=... (time_t when the file will be auto-deleted)
[Config]
Url=... (URL where the file was originally downloaded from)
SaveFilename=... (the file that is about to be deleted)