/usr/share/X11/xkb/symbols/rupeesign is in xkb-data 2.10.1-1ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 | // keyboards having the RupeeSign on the 4 key
partial
xkb_symbols "4" {
key <AE04> { [ NoSymbol, NoSymbol, U20B9 ] };
};
|