The current revision number of a cluster node is contained in a file at crx-quickstart/repository/revision.log. As is contents is binary it is needed to be displayed in a hexadecimal editor and convert it into decimal with a calculator.
On *nix this becomes:
$ hexdump -C crx-quickstart/repository/revision.log
00000000 00 00 00 00 06 52 62 00 |.....Rb.|
00000008
$ echo "ibase=16; 06526200" | bc
106062336
So, this instance's revision is (decimal) 106062336.