I can' use 'tab' to give 4 space on editor or switch to next textfield on Chromium.
So I guess 'tab' short cut definition might be changed by unknown software, but where can I find a general kde shortcut configuration file?
Or is there a GUI to check all hotkeys at once?

KDE System Settings > Shortcuts



Standard Keyboard Shortcuts for Applications are saved to the kdeglobals.
Global Keyboard Shortcuts are saved to the kglobalshortcutsrc.

XDG Base Directory Specification: https://specifications.freedesktop.org/ ... atest.html

$XDG_CONFIG_HOME defines the base directory relative to which user specific configuration files should be stored. If $XDG_CONFIG_HOME is either not set or empty, a default equal to $HOME/.config should be used.