To use this, put these two files in their own directory along with a copy of jQuery 2.1.1
From within Chrome, go to the extensions window and click "Load Unpacked Extension" and point to the directory where you placed the files. After installing the extension, refresh any Trello board and it will add extra hour/card information to the header.
To get hours, you must start the title of your card with Nh, where N is the number of hours. i.e. 8h or 0.5h
This is based on Trello scraping code by Ethan Brown