It's the latest in the 2.0.x line:

https://github.com/thomas-mcdonald/bootstrap-sass/tree/v2.0.4.2

Currently identical to the 2.0-stable *branch*:

https://github.com/thomas-mcdonald/bootstrap-sass/tree/2.0-stable

Not sure whether it's better to use the v2.0.4.2 tag in this case or the 2.0-stable branch (which is subject to modification).