Cross-browser extension development is painful. All of the major browser platforms have completely different extension frameworks. And when we say different, we mean different: wildly incompatible languages, APIs and philosophies.
Ancho aims to remove the pain from cross-browser extension development by providing a single unified API for Internet Explorer, Firefox and Chrome (with other browser platforms to follow). Rather than create our own API, we have chosen to implement the Chrome API in IE and Firefox. This simplifies the problem since we don't have to implement anything for Chrome. You will be able to use existing Chrome extensions out of the box. And you won't have to lock yourself into a proprietary API from a small vendor who might disappear into the sunset at any moment.
Ancho is under active development. We hope to have a beta version completed soon. We'll post more documentation at that time. In the meanwhile, you can post issues here if you have any inquiries.