Thank you for your answer.
Once codes are learnt, if I can get their pronto format, tools as IRTool or IRScope give me the protocol, device number, command number, ....
Now I can try to generate other codes for the same device to discover discrete codes if the original remote lacks them.
Sometimes also I don't remember in which database I found the code programmed in a MX980 button, and having it in pronto hex format would help recover this info (or compare the code with another one).
Once programmed in a button, the code becomes "inaccessible", and I feel that as a little frustrating...