org-capture in Firefox EXWM buffers

org-capture-firefox.el

(defun elmord-exwm-get-firefox-url ()
  (exwm-input--fake-key ?\C-l)
  (sleep-for 0.1) ;; Wish I could get rid of the sleeps...
  (exwm-input--fake-key ?\C-c)
  (sleep-for 0.1)
  (gui-backend-get-selection 'CLIPBOARD 'STRING))

(defun elmord-exwm-org-store-link ()
  (when (and (equal major-mode 'exwm-mode)
             (member exwm-class-name '("Firefox" "Firefox-esr")))
    (org-store-link-props
     :type "http"
     :link (elmord-exwm-get-firefox-url)
     :description exwm-title)))

(add-to-list 'org-store-link-functions 'elmord-exwm-org-store-link)