C45g, where to find this ECO code? I have a text file with 10K+ ECO opening codes from the Scid source distribution, for example:

C45g Scotch: Steinitz, Berger Variation
C45q Scotch: 4.Nxd4 Bc5 5.Nb3 Bb6 6.a4 a6 7.Nc3 Qf6


I know C45 is the code for Scotch Game, but I'm not sure C45g and C45q are valid.

Q: Are C45g and C45q valid? Should I just rename them to C45? If they're valid, where should I look up for more information?
These codes are the extended ECO codes by SCID, and have no meaning outside it.

When classifying the games you can enable or disable the extended ECO codes to force SCID to use the standard ones, if you prefer so.

There's a short explanation of the reason for the extended ECO codes here: https://sourceforge.net/p/scid/wiki/TheECObrowser/