It's a narrow support tool, not something you'll normally see. It only appears when all of the following are true: you're a SuperAdmin, you're viewing the profile within a single active location/reseller context, you loaded the page with ?stripe_cust=1 added to the URL (nothing in the UI adds this for you), and the customer already has a Stripe customer ID saved on the currently active Stripe account. Clicking it clears that stored Stripe customer reference from the user's record — useful for cleaning up a broken or duplicate Stripe link, not something regular admins need or can even see.