Download of XulBrowser 1.0 for Mac was available from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. This free Mac application was originally designed by R.J. Keller. We recommend checking the downloaded files with any free antivirus. The following version: 1.0 was the most frequently downloaded one by the program users. The application is included in Internet & Network Tools.
From the developer:
XulBrowser is a internet web browser written in Java that is designed to run trusted web applications as if they were normal applications like Microsoft Word. Applications are executed in their own window using XUL and JS for application code. The program code is put on your web server where the client can run it like an actual program.
You may want to check out more software for Mac, such as ryc-server or EdBrowser, which might be similar to XulBrowser.