<s>
Google	B-Application
Kythe	I-Application
is	O
a	O
source	O
code	O
indexer	O
and	O
cross-referencer	O
for	O
code	B-General_Concept
comprehension	I-General_Concept
which	O
describes	O
itself	O
as	O
a	O
"	O
pluggable	O
,	O
(	O
mostly	O
)	O
language-agnostic	O
ecosystem	O
for	O
building	O
tools	O
that	O
work	O
with	O
code	O
"	O
.	O
</s>
<s>
The	O
core	O
of	O
Google	B-Application
Kythe	I-Application
is	O
in	O
defining	O
language-agnostic	O
protocols	O
and	O
data	O
formats	O
for	O
representing	O
,	O
accessing	O
and	O
querying	O
source	O
code	O
information	O
as	O
data	O
.	O
</s>
<s>
Kythe	B-Application
relies	O
on	O
an	O
instrumented	O
build	O
system	O
and	O
compilers	O
that	O
produce	O
indexing	O
information	O
,	O
semantic	O
information	O
and	O
metadata	O
in	O
Kythe	B-Application
specified	O
format	O
.	O
</s>
<s>
This	O
information	O
obtained	O
from	O
running	O
an	O
instrumented	O
build	O
is	O
stored	O
in	O
a	O
language-agnostic	O
graph	B-Application
structure	O
.	O
</s>
<s>
Finally	O
,	O
this	O
graph	B-Application
structure	O
can	O
be	O
queried	O
to	O
answer	O
questions	O
about	O
the	O
code	O
base	O
.	O
</s>
<s>
Google	B-Application
Kythe	I-Application
is	O
an	O
open-source	B-Application
project	O
being	O
developed	O
by	O
Google	B-Application
.	I-Application
</s>
<s>
Google	B-Application
Kythe	I-Application
originates	O
from	O
an	O
internal	O
project	O
called	O
Grok	O
.	O
</s>
<s>
Some	O
parts	O
of	O
Grok	O
were	O
publicly	O
released	O
even	O
before	O
Google	B-Application
Kythe	I-Application
was	O
announced	O
.	O
</s>
<s>
In	O
2010	O
,	O
Google	B-Application
released	O
a	O
Python	O
static	O
analyzer	O
which	O
has	O
been	O
developed	O
as	O
part	O
of	O
Grok	O
.	O
</s>
<s>
In	O
2012	O
,	O
C++	B-Language
,	O
Java	B-Language
,	O
Python	O
,	O
JS	O
and	O
"	O
2	O
internal	O
languages	O
"	O
were	O
supported	O
by	O
Grok	O
.	O
</s>
<s>
There	O
was	O
an	O
Emacs	B-Application
client	O
.	O
</s>
<s>
Chromium	B-Language
Code	O
Search	O
Browser	O
uses	O
Grok	O
index	O
to	O
provide	O
quick	O
links	O
to	O
definition	O
for	O
every	O
symbol	O
in	O
the	O
source	O
code	O
.	O
</s>
