This is the source code of the Salesforce Workbench Chrome Extension, that you can install from here: https://chrome.google.com/webstore/detail/workbench-tools-for-googl/nanhambbggdgkloeldahjngdmngjgmhk
Feel free to contribute or to log issues in this repository.
Workbench is a PHP app which must be installed locally https://github.com/forceworkbench/forceworkbench