There's not really anything to elaborate on. The format was never published, so you should not find any documentation. It's also not something that needs to be used (except to convert to GeoTIFF).
Esri tools (including Pro) will read Grid format (if it hasn't been mangled in transfer). The important thing to understand is that grid is a folder structure, so the parent directory and parallel "info" folder are critical. Moving just the files is more likely to mangle the data.
- V