Find the source of an alias in bash

This is borderline embarrassing but by blogging about it, at least there's hope that I will not forget this.

If you have an executable, you can type which to find out its full path. For example:

$ which fdfind
/usr/bin/fdfind

then you can do something with that. But if the executable is an alias? E.g. I have set up alias fd='fdfind' and suppose I don't remember that. I have this executable, gbranch, but you can't use which on it:

$ which fd

It outputs nothing and you get an exit code of 1.

Lo and behold, it's so basic, run the alias command on it:

$ alias fd
alias fd='fdfind'