I was going through searching for undocumented breaking changes (ie there were a lot) during the Angular2 alpha phase and stumbled on 'y'.
Click a line, press y, and it changes to the commit where that line was last changed. Since it shows the tag the commit applies to up top, it's relatively easy to mark what release was affected by a specific breaking change.
It is similar to it, here are few differences:
1) Regex search
2) Performance - most of the data is locally cached
3) IDE like experience and a one click/swipe to move back to previous file without having to visit an intermediate page, not much of a plus but yeah!
Based on the feedback/usage I hope to build more features like goto method/variable definition to make it a more complete product.