This option takes you to the Documentation page at the ImageJ site (not this portal).
This command opens a browser and takes you to the Documentation section of the ImageJ website: http://rsb.info.nih.gov/ij/docs/
In linux, the command expects any of the following browsers installed (tested in this order): netscape, firefox, konqueror, mozilla, opera, epiphany or lynx. If you want a particular browser to be launched, here is a simple solution.