Usually under the recording info, they put what it was sourced from. They aren't specific about the release that it was sourced from but I would imagine this has to be somewhat above board or it would've already been shut down by Sony. This is the one for Kind of Blue.
Recording Info: Recorded at Columbia 30th Street Studio, New York City,
On March 2, 1959 (#1-3) And April 22, 1959 (#4 & 5)
Sourced from a 15ips 2-track tape
Analog: Transferred using a modified Studer 810 tape deck feeding a Merrill Tape Preamp
Digital: Merging Hapi Analog to Digital Converter clocked by a Antelope Audio 10MX Atomic Clock
Power Conditioning: Shunyata Research Everest 8000 for analog components
Shunyata Research Triton and Typhon for digital components