What does a/ and b/ stands for in patch header? The first line of patches always has this kind of code:

diff --git a/i18nviews.inc b/i18nviews.inc


or 

diff --git a/plugins/views_plugin_localization.inc b/plugins/views_plugin_localization.in


What does the a and b  stand for?
A' and the 'B' are prefixes to differentiate source and destination.

You can change the prefixes with 

--src-prefix=&lt;prefix&gt;
Show the given source prefix instead of "a/".

--dst-prefix=&lt;prefix&gt;
Show the given destination prefix instead of "b/".


From http://git-scm.com/docs/git-format-patch