(with-eval-after-load "eww"
  (define-key eww-mode-map "f" 'eww-lnum-follow)
  (define-key eww-mode-map "F" 'eww-lnum-universal))
(defun eww-lnum-read-interactive--not-truncate-lines (&rest them)
  (let ((truncate-lines nil))
    (apply them)))
(advice-add 'eww-lnum-read-interactive :around
            'eww-lnum-read-interactive--not-truncate-lines)