Historical Rules · 29 April 2022
Rule 702.6e
Official source text from the 29 April 2022 Rules release
“Equip planeswalker” is a variant of the equip ability. “Equip planeswalker [cost]” means “[Cost]: Attach this permanent to target planeswalker you control as though that planeswalker were a creature. Activate only as a sorcery.”