Samuel Yates began, and this site continues, a database of the largest known primes. Primes in that database are assigned a proof-code to show who should be credited with the discovery as well as what programs and projects they used. (Discoverers have one prover-entry, but may have many proof-codes because they use a variety of programs...)
This page provides data on g399, one of those codes.
Code name (*): g399 Persons (*): 1 (counting humans only) Projects (*): 0 (counting projects only) Display (HTML): Pacini, NewPGen, PRP, Proth.exe Number of primes: total 1 Unverified Primes: 0 (prime table entries marked 'Composite','Untested', or 'InProcess' Score for Primes (*): total 40.4518
Below is additional information about this entry.
Display (text): Pacini, NewPGen, PRP, Proth.exe Display (short): Pacini Database id: 1176 (do not use this database id, it is subject to change) Proof program: Proth.exe Entry last modified: 2021-10-23 00:37:15