I think you're referring to the foot education site with the peer-reviewed rehab for pretty severe tendon inflammation and a chronic condition. I agree, that site is just fabulous and really explains what's happening in the foot.

I also found the initial youtube link exercises valuable in the past two days. My legs feel straighter after doing the pen-penny exercise, and seeing that, yes, there is a muscle there that can lift the arch and take the strain off the stretched-out and inflamed posterior tibial tendon. I can walk without joint pain, suddenly. I feel like I can build this muscle.

The physiotherapist told me to swim, and that was good, but instead of giving me decent exercises he said one day I'd be able to stretch my calf on an incline board, and he just set me up with various kinds of electromagnetic pulse stimulation that I felt were worse than useless. Cautiously trying these exercises has been most valuable.