From the FAQ
Q: In what facility has Bluetooth been implemented?
A: The main function is to setup a data connection to a 3G enabled mobile phone (dial-up) in order to connect to the internet. Other functions can be added depending customer requests.
Q: Will there be a web browser on the device and if so which one and will it support Java?
A: Yes, the iRex Digital Reader 1000 SW will have a limited browser (web-kit based). It will support text and images, non-supported formats (e.g. flash) will be replaced by content that can be displayed (static images) or ignored. It supports java scripting, radio buttons, checkboxes, input fields, buttons and downloading files.
Based on the effort involved in porting FBReader, probably any lightweight GTK+ based web browser could be ported to the DR.