I know the typical envelopes (gain/Pan etc) and how to use the edit filter to display them or not.  But I have one track that has an envelope that I can not delete or identify. (Because this is an old file and I don't remember what I did to it)And no matter what I select in the track edit filter it is  still there.  It is a dark green and it only shows up in the track pane.  Not the clips pane.  what is it?  Is there a global delete all automation command?

you can turn automation off on that track if you don't need it at all for this track.
just click the "R" button until it turns off (no longer eliminated).

You could use Edit > Delete Special > Deselect everything apart from Track Automation
 
Or.....enable the Automation Lanes to see what's exposed.