I think it's this one https://www.dropbox.com/s/edro842mg6...ndarWidget.apk
It's a proof of concept calendar widget made by a famous developer the name of which escapes me now. It doesn't do anything other than displaying the current month though so it's not very useful. It's plenty pretty though
It's similar to this one from APW. Difference being with APW's you can toggle between month and agenda (daily planner) view, move between months, and use the header to launch an app and to create a new task or appointment. It's also as you can see available as a lock screen widget.
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