In a nutshell, you can make copies of the original and modified copies of the RFX library source code for your personal use, but you can’t distribute the source, in either original or modified form, to third parties.
You can distribute any compiled/linked object/executable code without restriction, however.
Finally, there are the standard “DBAA” conditions: Use responsibly. Deploy any systems you build with due care and respect for the inherent limitations of the software and hardware. If you do anything that results in causing anyone or anything harm, all liability rests with you, not us.
That’s pretty much the gist of it. To see how this compiles into legalese (which is perhaps only rivaled for verbosity by COBOL), read the full EULA.