<s>
Yelp	B-Language
,	O
also	O
known	O
as	O
the	O
GNOME	B-Application
Help	O
Browser	O
is	O
the	O
default	O
help	O
viewer	O
for	O
GNOME	B-Application
that	O
allows	O
users	O
to	O
access	O
help	O
documentation	O
.	O
</s>
<s>
Yelp	B-Language
follows	O
the	O
freedesktop.org	B-Application
help	O
system	O
specification	O
and	O
reads	O
mallard	B-Language
,	O
DocBook	B-Protocol
,	O
man	B-Protocol
pages	I-Protocol
,	O
info	B-Protocol
,	O
and	O
HTML	O
documents	O
.	O
</s>
<s>
HTML	O
is	O
available	O
by	O
using	O
XSLT	B-Application
to	O
render	O
XML	B-Protocol
documents	I-Protocol
into	O
HTML	O
.	O
</s>
<s>
Yelp	B-Language
has	O
a	O
search	O
feature	O
as	O
well	O
as	O
a	O
toolbar	O
at	O
the	O
top	O
for	O
navigation	O
through	O
previously	O
viewed	O
documentation	O
.	O
</s>
<s>
Because	O
it	O
functions	O
as	O
a	O
type	O
of	O
web	O
browser	O
,	O
it	O
uses	O
Firefox	B-Application
as	O
a	O
dependency	O
and	O
Firefox	B-Application
must	O
be	O
installed	O
in	O
order	O
to	O
use	O
yelp	B-Language
.	O
</s>
<s>
Yelp	B-Language
can	O
be	O
accessed	O
by	O
typing	O
either	O
into	O
GNOME	B-Language
Shell	I-Language
,	O
after	O
pressing	O
within	O
GNOME	B-Application
,	O
or	O
within	O
a	O
terminal	O
using	O
the	O
format	O
.	O
</s>
<s>
The	O
command	O
can	O
also	O
be	O
used	O
to	O
access	O
Yelp	B-Language
.	O
</s>
<s>
Although	O
Yelp	B-Language
is	O
not	O
required	O
for	O
GNOME	B-Application
to	O
function	O
,	O
it	O
is	O
required	O
to	O
view	O
GNOME	B-Application
's	O
help	O
documentation	O
.	O
</s>
<s>
Ubuntu	B-Operating_System
also	O
uses	O
yelp	B-Language
to	O
provide	O
a	O
customized	O
help	O
interface	O
for	O
its	O
software	O
.	O
</s>
<s>
A	O
format	B-Language
string	I-Language
vulnerability	O
in	O
GNOME	B-Application
versions	O
2.19.90	O
and	O
2.24	O
allowed	O
arbitrary	O
code	O
execution	O
through	O
Yelp	B-Language
.	O
</s>
