urxvt-keysym-list man page
keysym-list — implement the "list" keysym expansion.
urxvt -pe keysym-list
The "list" keysym expansion was formerly part of the rxvt-unicode core, and has been moved into this extension for backwards compatibility. You shouldn't use this extension except for compatibility with old configurations.
urxvt256c-keysym-list(1), urxvt256c-ml-keysym-list(1) and urxvt-ml-keysym-list(1) are aliases of urxvt-keysym-list(1).