V70, 2006, Auto, 128K, Foot on brake, but can't move selector to drive. Obviously an interlock somewhere.

 

Yes there is an interlock. It's a separate plug in part, on a bracket and it contacts the brake pedal hardware.
It's down low. I saw it in a brake video. See if you can locate yours and if it's plugged in.

I just tried to find the video and failed. One post I read mentioned the actual lock part is at the base of the shift lever and can be rendered sticky by spilled beverages. A fellow suggested to another guy with your problem that a sharp rap downward on the lever might free it up.

Possibly gain access by removing the console cover and see if it can be removed or set aside securely?