I'm not sure about the it band, but foam rolling my calves massively decreases the pain and tightness I get from walking, and if I make foam rolling a habit, I no longer get pain.

Also, it's possible the pain is gone from just walking a lot but it don't think this is the case because I get pain if I walk a lot and don't foam roll.

Good chance that foam rolling does 0 for your calf muscles/tendons, but breaks up the bonds of sticking fascia, which tfa doesn't touch upon at all.

Foam rolling doesn't need to be overdone, either.

The why of trigger point therapy is almost certainly wrong, but the results are unquestionable.