NEW - Biden says "The president wrote a very generous letter," referring to Trump. "Because it was private, I won't talk about it until I talk to him. But it was generous."
This taken from the US Military Voice Telegram Channel.
I'm betting the 'generosity' was the deal Biden cut with Trump...
Tbh, it would just mean Trump was kind. Probably good luck, you can do it, all the bullshit platitudes under the sun.
He probably didn't expect a letter at all. I wouldn't read into it.