There seems to be some interest to port Rubi to Sage. See the link to sage-devel. In particular the licence for Rubi might need some clarification.
>> The mathematical knowledge on this website is freely available for >> any educational, academic or commercial use. Please include the >> website address and appropriately acknowledge its author in any >> product incorporating its contents.
Jeroen Demeyer writes:
> Such an acknowledgement (similar to the OpenSSL license) would be > incompatible with the GPL.