The web browser kept crashing after installing microb, so I removed the .browser file, every time I restarted the browser the file would be recreated with engine=microb under the [Settings] section of the file.
The only fix was to kill all the browser apps (kill [pid] in xterm) and then edit the file myself. To use the Opera based engine, you change it to engine=opera. You can also change hidden=false, this is supposed to display a menu option below the close button that allows you to select the engine, I have yet to see this option though...
