There is an archive of one of the documents here: Myriad RF for Arduino Projects?
After speed reading the document, it looks like it uses the standard Arduino SPI comunications library.
So PC<-USB->Arduino<-SPI->LMS
I do not think that the missing control library will be a magic bullet.
You would still need to understand the Serial Port Interface section of the datasheet:
LMS6002Dr2-DataSheet-1.2r0.pdf @ https://github.com/myriadrf/LMS6002D-docs
And fully understand all the programming registers and their correct usage:
LMS6002Dr2-Programming and Calibration Guide-1_1r4.pdf @ https://github.com/myriadrf/LMS6002D-docs
My guess would be that the information was made inaccessible, by accident, on a server data migration - but I’m only guessing.
There is a sample file here using SPI to communicate with a LMS7002M, but the method would be similar for a LMS6002D - it is not trivial. Control LimeSDR via SPI using Arduino MCU