Expanse vs. Slate: are they the same pedal?

Internally, yes — the Expanse and the Slate are the same pedal. The one practical difference: the Slate's top surface could be re-labeled with a Sharpie marker. That won't work on the Expanse. The whole previous line of stereo reprogrammable pedals — Wet Stereo Reverb, Seraphim Stereo Shimmer, Chroma Stereo Chorus, Echelon Stereo Echo, and the Slate Stereo Programmable pedal — was consolidated and rebranded as Expanse with new artwork.