~/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-keyboard-shortcuts.xml
konsole hotkeys
~/.kde/share/config/konsolerc
~/.kde/share/apps/konsole
~/.kde/share/apps/konsole/konsoleui.rc
~/.kde/share/apps/konsole/konsole
~/.config/konsolerc
~/.kde/share/apps/konsole
~/.kde/share/apps/konsole/konsoleui.rc
~/.kde/share/apps/konsole/konsole
~/.config/konsolerc
xfce4-volumedAUR maps volume keys to xfce-mixer, and displays notifications through xfce4-notifyd. When using PulseAudio, use xfce4-volumed-pulseAUR instead. See also #Xfce4-mixer and pulseaudio.
If you are using PulseAudio and do not wish to use Xfce4 mixer, you could use xfce4-pulseaudio-pluginAUR instead. This package provides a mixer applet for the panel and has support for the keyboard volume keys.
For non desktop environment specific alternatives, see List of applications#Volume managers.