nl_tokens: https : // dom . spec . whatwg . org / #find - slotables
pl_tokens: function findSlotable ( slot ) { const result = [ ] ; const root = getRoot ( slot ) ; if ( ! isShadowRoot ( root ) ) { return result ; } for ( const slotable of domSymbolTree . treeIterator ( root . host ) ) { const foundSlot = findSlot ( slotable ) ; if ( foundSlot === slot ) { result . <mask> ( slotable ) ; } } return result ; }