http://3cbzkrvakrpetjjppdwzbzqrlkmzatjs7jbyazap5gwutj32gcltjpqd.onion
To my surprise xev showed that this “thumb button” press was actually sending Control and Alt keypress events: $ xev
KeyPress event, serial 52, synthetic NO, window 0x2c00001,
root 0x413, subw 0x0, time 3233018, (58,87), root:(648,579),
state 0x10, keycode 37 (keysym 0xffe9, Alt_L), same_screen YES,
XLookupString gives 0 bytes:
XmbLookupString gives 0 bytes:
XFilterEvent returns: False
KeyPress event, serial 52, synthetic NO, window 0x2c00001,
root 0x413, subw 0x0, time...