I have installed some dotfiles which have over ridden ALT + "." to call the last parameter to previous command. Where is this setting stored by default as I m guessing these dotfiles must have over ridden that .
It can be set by a bind command in any of your startup files such as /etc/profile, /etc/profile.d/*, ~/.profile, ~/.bashrc, etc. Or it can be set in /etc/inputrc or ~/.inputrc.
The default, if nothing is set explicitly, is set internally in Bash.