Git – “blame” a deleted line
If you know the contents of the line:
$ git log -S <string> path/to/file
which shows you commits that introduced or removed an instance of the given string.
$ git log -G <regex> path/to/file
which does the same thing with regular expressions.
Alternatively you can use:
$ git blame --reverse <sha1-commit-hash>..HEAD path/to/file
to see the latest revision in which the line existed.