Which tape to seal seams between XPS panels?
I ended up going with Owens Corning JointSealR Foam Joint Tape, as it's the only tape I could find that mentions working with XPS, specifically. From the manufacturer:


  Owens Corning JointSealR Foam Joint Tape is an effective product to tape the joints of FOAMULAR® extruded polystyrene (XPS) board in vertical wall applications when it is used as continuous insulation over steel or wood wall framing, or as masonry cavity wall insulation.


https://www.owenscorning.com/insulation/products/jointsealr-foam-joint-tape

I found only one place that sells it, and it wasn't cheap at $37.50 for a 90 ft. roll.