"((parent-id . 20506031)
(outer-window-id . \"52429003\")
(window-id . \"52429034\")
(top . 0)
(left . 2560)
(width . 282)
(height . 67)
(name . \"emacs [emacs-26] *scratch-emacs-lisp-mode**\")
(fullscreen-restore)
(explicit-name)
(icon-name)
(unsplittable)
(modeline . t)
(frameset--mini t . t)
(frameset--id . \"D44A-14E2-2416-0AA9\")
(display . \":1.0\")
(tty . \"/dev/pts/10\")
(tty-type . \"xterm-24bits\")
(sticky)
(cursor-color . \"white\")
(background-mode . dark)
(display-type . color)
(client . \"Unprintable entity\")
(z-group)
(skip-taskbar)
(visibility . t)
(fullscreen)
(no-accept-focus)
(no-focus-on-map)
(alpha)
(scroll-bar-height . 0)
(scroll-bar-width . 0)
(cursor-type . box)
(auto-lower)
(auto-raise)
(icon-type . t)
(inhibit-double-buffering)
(tool-bar-position . top)
(wait-for-wm . t)
(title)
(buffer-predicate)
(tool-bar-lines . 0)
(menu-bar-lines . 0)
(scroll-bar-background)
(scroll-bar-foreground)
(no-special-glyphs)
(right-fringe . 8)
(left-fringe . 8)
(line-spacing)
(screen-gamma)
(border-color . \"black\")
(mouse-color . \"black\")
(background-color . \"#282828\")
(foreground-color . \"#f7f7f7\")
(horizontal-scroll-bars)
(vertical-scroll-bars)
(bottom-divider-width . 0)
(right-divider-width . 1)
(internal-border-width . 0)
(border-width . 0)
(font-parameter . \"-unknown-PragmataPro-normal-normal-normal-*-18-*-*-*-*-0-iso10646-1\")
(font . \"-unknown-PragmataPro-normal-normal-normal-*-18-*-*-*-*-0-iso10646-1\")
(font-backend xft x)
(override-redirect)
(undecorated)
(parent-frame)
(minibuffer . t))
"
Now frame-parameters is a C function and somehow derives the client parameter to be "Unprintable entity". Let me know how I can further debug this.