When I run:
git difftool -d
It creates a temporary directory containing the files to be shown in the diff. The structure looks like this:
tmpdir/
left/
file1
lindex
right/
file1
rindex
The "left" and "right" directories are clear. But what are the "lindex" and "rindex" files? What do they contain? How can I view them? Sometimes there's no "rindex" but a "wtindex" file instead.