You can also view it on Councilmatic: https://nyc.councilmatic.org/legislation/int-1017-2015/

Shows the same info as Legistar including all 33 sponsors and every legislative action taken over the last year.

You're probably referring to http://opengovernment.org/ by the Sunlight Foundation and Participatory Politics Foundation (PPF).

The work continues! My company DataMade is working with PPF to make local legislation more accessible, starting with Chicago, New York and Philly: http://councilmatic.org/