I can see it here in later versions:
But I’m editing code for version 2.1.40, which has a different file structure and some different file names. I don’t expect anyone to know exactly where it is in old versions but some general guidance on where to look would be appreciated. I searched all the files in the anki/rslib/src/sched at 2.1.40 · ankitects/anki · GitHub folder.
Are there separate functions for review and learning cards?