pxls
perl X listing app
pxls # list any X app with any atom (xlsclient only lists WM_COMMAND apps)
pxls -a # show attributes too
pxls -A # show all apps even ones without atoms
pxls -e # show X extensions
e.g.
$ pxls | head
QueryTree(1946)
|- Window 0x 600011:
| WM_LOCALE_NAME (313) <C>
| WM_CLASS ( 67) <xconsole>, <XConsole>
| WM_CLIENT_MACHINE( 36) <xxxxxxx.xxxxx.xxx>
| WM_COMMAND ( 34) </usr/X11R6/bin/xconsole>, <-geometry>, <480x130-0-0>, <-daemon>, <-notify>, <-verbose>, <-fn>, <fixed>, <-exitOnFail>
| WM_ICON_NAME ( 37) <xconsole>
| WM_NAME ( 39) <xconsole>
|- Window 0x a0000c:
| WM_LOCALE_NAME (313) <en_US.UTF-8>