The Recovery Bastion "heals nearby friendly units".
I'm a numbers person. One of my peeves is vague information about what things can do, whether units or buildings. Give me some data I can use please. "Nearby" tells me nothing. It could mean the entire base or it could mean 50 distance. Since the Recovery Bastion irritatingly shows no range ring when I hold my mouse over it, I am inclined to never use it.
How far exactly is "nearby"?