<s>
about	O
is	O
an	O
internal	O
URI	B-Protocol
scheme	O
(	O
also	O
known	O
as	O
a	O
"	O
URL	O
scheme	O
"	O
or	O
,	O
erroneously	O
,	O
"	O
protocol	O
"	O
)	O
implemented	O
in	O
various	O
Web	B-Application
browsers	I-Application
to	O
reveal	O
internal	O
state	O
and	O
built-in	O
functions	O
.	O
</s>
<s>
In	O
early	O
versions	O
of	O
Netscape	B-Protocol
,	O
any	O
URI	B-Protocol
beginning	O
with	O
about	B-Protocol
:	I-Protocol
that	O
was	O
n't	O
recognized	O
as	O
a	O
built-in	O
command	O
would	O
simply	O
result	O
in	O
the	O
text	O
after	O
the	O
colon	O
being	O
displayed	O
.	O
</s>
<s>
Similarly	O
,	O
in	O
early	O
versions	O
of	O
Internet	B-Application
Explorer	I-Application
,	O
about	B-Protocol
:	I-Protocol
followed	O
by	O
a	O
string	O
of	O
HTML	B-Language
(	O
e.g.	O
</s>
<s>
about:xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx1	O
)	O
would	O
render	O
that	O
string	O
as	O
though	O
it	O
were	O
the	O
source	O
of	O
the	O
page	O
—	O
thus	O
providing	O
a	O
similar	O
(	O
though	O
more	O
limited	O
)	O
facility	O
to	O
the	O
data	B-Protocol
:	I-Protocol
URI	I-Protocol
scheme	I-Protocol
defined	O
by	O
.	O
</s>
<s>
Still	O
other	O
versions	O
of	O
Netscape	B-Protocol
would	O
return	O
various	O
phrases	O
in	O
response	O
to	O
an	O
unknown	O
about	O
URI	B-Protocol
,	O
including	O
"	O
Whatchew	O
talkin	O
 '	O
'	O
bout	O
,	O
Willis	O
?	O
"	O
</s>
<s>
The	O
most	O
commonly	O
implemented	O
about	O
URIs	B-Protocol
are	O
about:blank	O
,	O
which	O
displays	O
a	O
blank	O
HTML	B-Language
document	O
,	O
and	O
simply	O
about	B-Protocol
:	I-Protocol
,	O
which	O
may	O
display	O
information	O
about	O
the	O
browser	B-Application
.	O
</s>
<s>
Some	O
browsers	B-Application
use	O
URIs	B-Protocol
beginning	O
with	O
the	O
name	O
of	O
the	O
browser	B-Application
for	O
similar	O
purposes	O
,	O
and	O
many	O
about	O
URIs	B-Protocol
will	O
be	O
translated	O
into	O
the	O
appropriate	O
URI	B-Protocol
if	O
entered	O
.	O
</s>
<s>
Examples	O
are	O
opera	B-Application
(	O
Opera	B-Application
)	O
or	O
chrome	B-Application
(	O
Google	B-Application
Chrome	I-Application
)	O
.	O
</s>
<s>
In	O
2010	O
,	O
and	O
onwards	O
,	O
there	O
are	O
efforts	O
to	O
standardize	O
the	O
about	B-Protocol
URI	I-Protocol
scheme	I-Protocol
,	O
and	O
define	O
the	O
processing	O
requirements	O
for	O
some	O
specific	O
URIs	B-Protocol
,	O
in	O
the	O
IETF	O
Applications	O
Area	O
Working	O
Group	O
(	O
APPSAWG	O
)	O
.	O
</s>
<s>
The	O
about	O
URIs	B-Protocol
that	O
have	O
since	O
been	O
defined	O
and	O
assigned	O
by	O
IANA	O
are	O
listed	O
below	O
.	O
</s>
<s>
URIPurpose	O
about:blankRFC	O
6694References	O
a	O
blank	O
HTML	B-Language
document	O
with	O
the	O
media	B-Application
type	I-Application
text/html	B-Language
and	O
character	O
encoding	O
UTF-8	O
.	O
</s>
<s>
This	O
is	O
widely	O
used	O
to	O
load	O
blank	O
pages	O
into	O
browsing	O
contexts	O
,	O
such	O
as	O
iframes	O
within	O
HTML	B-Language
,	O
which	O
may	O
then	O
be	O
modified	O
by	O
scripts	O
.	O
</s>
<s>
about:legacy-compatA	O
reserved	O
,	O
though	O
unresolvable	O
,	O
URI	B-Protocol
defined	O
within	O
HTML5	B-Application
intended	O
for	O
use	O
in	O
the	O
DOCTYPE	O
designed	O
for	O
compatibility	O
with	O
some	O
legacy	O
authoring	O
tools	O
,	O
such	O
as	O
XSLT	B-Application
,	O
which	O
may	O
not	O
be	O
capable	O
of	O
outputting	O
the	O
more	O
common	O
,	O
shorter	O
alternative	O
that	O
lacks	O
both	O
the	O
PUBLIC	O
and	O
SYSTEM	O
identifiers	O
.	O
</s>
<s>
<!DOCTYPE html SYSTEM "about:legacy-compat">	O
.	O
</s>
<s>
about:srcdocA	O
reserved	O
,	O
though	O
unresolvable	O
,	O
URI	B-Protocol
defined	O
within	O
HTML5	B-Application
intended	O
to	O
be	O
the	O
URI	B-Protocol
navigated	O
to	O
within	O
iframes	O
whose	O
content	O
comes	O
from	O
the	O
srcdoc	O
attribute	O
.	O
</s>
<s>
about:html-kindUsed	O
as	O
an	O
identifier	O
for	O
kinds	O
of	O
media	O
tracks	O
.	O
</s>
<s>
+	O
Common	O
"	O
about	B-Protocol
:	I-Protocol
"	O
URIsURIPurpose	O
Firefox	B-Application
,	O
SeaMonkey	B-Language
,	O
Mozilla	B-Language
Google	B-Application
Chrome	I-Application
,	O
Chromium	B-Language
Konqueror	B-Application
Opera	B-Application
Edge	B-Application
Internet	B-Application
Explorer	I-Application
about	B-Protocol
:	I-Protocol
Redirects	O
to	O
"	O
chrome://version	O
"	O
Redirects	O
to	O
"	O
about:konqueror	O
"	O
Redirects	O
to	O
"	O
opera:about	O
"	O
Redirects	O
to	O
"	O
edge://version	O
"	O
about:about	O
Lists	O
all	O
the	O
about	B-Protocol
:	I-Protocol
URLs	I-Protocol
(	O
Firefox	B-Application
since	O
version	O
4.0	O
)	O
Redirects	O
to	O
"	O
chrome://about	O
"	O
;	O
Lists	O
all	O
the	O
chrome	B-Application
:	O
URIs	B-Protocol
(	O
Works	O
like	O
"	O
chrome://chrome	O
-urls	O
"	O
)	O
Redirects	O
to	O
"	O
about:konqueror	O
"	O
Redirects	O
to	O
"	O
opera:about	O
"	O
Redirects	O
to	O
"	O
edge://edge	O
-urls	O
"	O
about:blank	O
Shows	O
a	O
blank	O
document	O
about:plugins	O
Shows	O
the	O
filename	O
,	O
MIME	B-Application
type	I-Application
,	O
description	O
,	O
suffix	O
,	O
and	O
status	O
of	O
all	O
installed	O
plug-ins	O
Shows	O
the	O
filename	O
,	O
MIME	B-Application
type	I-Application
,	O
description	O
,	O
suffix	O
,	O
and	O
status	O
of	O
all	O
installed	O
plug-ins	O
Redirects	O
to	O
"	O
opera:plugins	O
"	O
about:cache	O
Shows	O
information	O
about	O
the	O
Cache	O
Service	O
.	O
</s>
<s>
Redirects	O
to	O
"	O
about:konqueror	O
"	O
Redirects	O
to	O
"	O
opera:cache	O
"	O
about:mozilla	B-Application
Shows	O
a	O
page	O
from	O
the	O
fictional	O
Book	B-Application
of	I-Application
Mozilla	I-Application
.	O
</s>
<s>
In	O
some	O
versions	O
of	O
Netscape	B-Protocol
,	O
also	O
replaced	O
the	O
meteors	O
in	O
the	O
standard	O
Netscape	B-Protocol
throbber	O
with	O
a	O
large	O
fire-breathing	O
lizard	O
.	O
</s>
<s>
Redirects	O
to	O
"	O
about:konqueror	O
"	O
Shows	O
a	O
blank	O
HTML	B-Language
document	O
with	O
a	O
blue	O
background	O
.	O
</s>
<s>
Removed	O
in	O
Windows	B-Application
XP	I-Application
SP2	O
.	O
</s>
<s>
The	O
following	O
applies	O
to	O
all	O
web	B-Application
browsers	I-Application
that	O
derive	O
from	O
the	O
Chromium	B-Language
project	I-Language
,	O
including	O
Google	B-Application
Chrome	I-Application
,	O
Microsoft	B-Application
Edge	I-Application
,	O
Opera	B-Application
,	O
and	O
Vivaldi	B-Language
.	O
</s>
<s>
+	O
Chrome-specific	O
"	O
about	B-Protocol
:	I-Protocol
"	O
URIs	B-Protocol
URI	B-Protocol
Purpose	O
about:cache	O
Deprecated	O
in	O
version	O
66	O
about:crash	O
Crashes	O
the	O
current	O
rendering	O
process	O
.	O
</s>
<s>
about:credits	O
Displays	O
the	O
list	O
of	O
free	O
and	O
open	O
source	O
software	O
used	O
in	O
the	O
browser	B-Application
,	O
and	O
their	O
associated	O
licenses	O
.	O
</s>
<s>
about:dino	O
Displayed	O
when	O
the	O
browser	B-Application
cannot	O
connect	O
to	O
the	O
target	O
URL	O
,	O
this	O
page	O
contains	O
an	O
Easter	O
Egg	O
:	O
Pressing	O
the	O
Space	O
Bar	O
key	O
starts	O
the	O
_Dino_	O
minigame	O
,	O
which	O
involves	O
making	O
a	O
dinosaur	O
jump	O
over	O
obstacles	O
.	O
</s>
<s>
Microsoft	B-Application
Edge	I-Application
does	O
n't	O
feature	O
this	O
page	O
,	O
having	O
replaced	O
it	O
with	O
about:surf	O
(	O
see	O
below	O
.	O
)	O
</s>
<s>
about:histograms	O
Displays	O
histograms	O
about:inducebrowsercrashforrealz	O
Crashes	O
the	O
Google	B-Application
Chrome	I-Application
browser	I-Application
.	O
</s>
<s>
This	O
is	O
designed	O
for	O
developers	O
to	O
test	O
what	O
happens	O
when	O
the	O
Google	B-Application
Chrome	I-Application
browser	I-Application
crashes	O
.	O
</s>
<s>
Additionally	O
,	O
crashes	O
Chromebooks	O
entirely	O
due	O
to	O
them	O
running	O
on	O
Google	B-Application
Chrome	I-Application
.	O
</s>
<s>
about:internets	O
On	O
particular	O
versions	O
of	O
Windows	B-Application
,	O
displays	O
a	O
page	O
entitled	O
"	O
Do	O
n't	O
Clog	O
the	O
Tubes	O
!	O
"	O
</s>
<s>
which	O
renders	O
a	O
page	O
with	O
an	O
animation	O
of	O
the	O
Microsoft	B-Application
Windows	I-Application
"	O
3D	O
Pipes	O
"	O
screensaver	O
.	O
</s>
<s>
Does	O
not	O
work	O
on	O
Windows	B-Application
Vista	I-Application
due	O
to	O
the	O
pipes	O
screen	O
saver	O
no	O
longer	O
being	O
supported	O
for	O
releases	O
after	O
the	O
2.0.169.1	O
release	O
.	O
</s>
<s>
Occurs	O
when	O
the	O
OS	O
runs	O
out	O
of	O
memory	O
or	O
the	O
browser	B-Application
is	O
killed	O
by	O
an	O
external	O
cause	O
,	O
such	O
as	O
the	O
OS	O
shutting	O
down	O
.	O
</s>
<s>
about:labs	O
Moved	O
to	O
about:flags	O
in	O
Chrome	B-Application
Dev	O
channel	O
8.0.552.11	O
about:memory	O
Displays	O
the	O
process	O
manager	O
about:net-internals	O
Provides	O
an	O
interface	O
for	O
monitoring	O
the	O
network	O
usage	O
and	O
performance	O
statistics	O
about:plugins	O
Shows	O
installed	O
plug-ins	O
(	O
Deprecated	O
in	O
Chrome	B-Application
57	O
)	O
about:sandbox	O
Shows	O
which	O
sandbox	O
protection	O
mechanisms	O
are	O
currently	O
enabled	O
.	O
</s>
<s>
about:version	O
Displays	O
version	O
information	O
,	O
same	O
as	O
about	B-Protocol
:	I-Protocol
</s>
<s>
The	O
above	O
list	O
is	O
not	O
exhaustive	O
;	O
for	O
a	O
full	O
list	O
,	O
see	O
about:about	O
URI	B-Protocol
.	O
</s>
<s>
Also	O
,	O
some	O
extensions	O
define	O
additional	O
about	B-Protocol
:	I-Protocol
URIs	B-Protocol
not	O
listed	O
here	O
.	O
</s>
<s>
+	O
Mozilla-specific	O
"	O
about	B-Protocol
:	I-Protocol
"	O
URIsURIsPurpose	O
Firefox	B-Application
SeaMonkey	B-Language
,	O
Mozilla	B-Language
Application	I-Language
Suite	I-Language
about:addons	O
Shows	O
installed	O
addons	O
,	O
plugins	O
,	O
themes	O
,	O
and	O
provides	O
an	O
interface	O
for	O
installing	O
new	O
addons	O
(	O
Firefox	B-Application
4+	O
and	O
SeaMonkey	B-Language
2.1	O
+	O
)	O
about:app-manager	O
Shows	O
the	O
Firefox	B-Operating_System
OS	I-Operating_System
Simulator	O
about:bloat	O
Displays	O
BloatView	O
output	O
(	O
disabled	O
in	O
release	O
builds	O
)	O
.	O
</s>
<s>
Superseded	O
by	O
about:memory	O
on	O
Gecko	O
1.9.2	O
.	O
about:bloat	O
?	O
new	O
TBA	O
about:bloat	O
?	O
clear	O
TBA	O
about:blocked	O
Shows	O
the	O
malware	O
protection	O
page	O
used	O
when	O
the	O
browser	B-Application
identifies	O
a	O
page	O
as	O
not	O
safe	O
for	O
viewing	O
(	O
Firefox	B-Application
3+	O
)	O
about:buildconfig	O
Shows	O
the	O
arguments	O
and	O
options	O
used	O
to	O
compile	O
the	O
build	O
in	O
use	O
about:cache	O
Shows	O
information	O
about	O
the	O
Cache	O
Service	O
.	O
</s>
<s>
about:cache	O
?	O
device	O
=	O
memory	O
Shows	O
individual	O
entries	O
in	O
memory	O
about:cache	O
?	O
device	O
=	O
disk	O
Shows	O
individual	O
entries	O
on	O
disk	O
about:cache	O
?	O
device	O
=	O
offline	O
Shows	O
individual	O
entries	O
for	O
offline	O
viewing	O
(	O
Gecko	B-Language
1.9	I-Language
+	O
)	O
about:cache-entry	O
Shows	O
information	O
about	O
a	O
cache	O
entry	O
.	O
</s>
<s>
about:certerror	O
Shows	O
the	O
error	O
page	O
used	O
when	O
an	O
SSL/TLS	B-Protocol
certificate	O
is	O
untrusted	O
or	O
otherwise	O
invalid	O
about:config	O
Shows	O
an	O
interface	O
for	O
viewing	O
and	O
setting	O
a	O
wide	O
variety	O
of	O
configuration	O
variables	O
,	O
many	O
of	O
which	O
are	O
not	O
otherwise	O
accessible	O
through	O
the	O
GUI	B-Application
(	O
options	O
panels	O
)	O
.	O
</s>
<s>
The	O
known	O
earliest	O
use	O
of	O
about:config	O
dates	O
back	O
to	O
Netscape	B-Protocol
4.x	O
,	O
where	O
it	O
was	O
not	O
possible	O
to	O
edit	O
the	O
settings	O
from	O
the	O
browser	B-Application
.	O
</s>
<s>
about:config	O
settings	O
first	O
became	O
modifiable	O
in	O
Mozilla	B-Language
Application	I-Language
Suite	I-Language
.	O
</s>
<s>
The	O
message	O
about	O
voiding	O
one	O
's	O
warranty	O
is	O
a	O
joke	O
,	O
as	O
Mozilla	B-Application
Firefox	I-Application
ships	O
without	O
a	O
warranty	O
of	O
any	O
kind	O
.	O
</s>
<s>
about:crashes	O
Shows	O
details	O
of	O
crashes	O
submitted	O
by	O
Mozilla	B-Language
's	O
crash	O
reporter	O
(	O
Firefox	B-Application
3+	O
,	O
SeaMonkey	B-Language
2.0	O
+	O
)	O
about:credits	O
Shows	O
a	O
list	O
of	O
all	O
those	O
who	O
contributed	O
to	O
Mozilla	B-Language
about:devtools	O
Shows	O
the	O
welcome	O
page	O
used	O
by	O
Firefox	B-Application
Developer	O
Tools	O
about:downloads	O
Shows	O
a	O
list	O
of	O
downloaded	O
files	O
about:feeds	O
Shows	O
the	O
page	O
used	O
when	O
clicking	O
the	O
rss	O
feed	O
icon	O
in	O
the	O
address	O
bar	O
about:healthreport	O
Shows	O
the	O
Firefox	B-Application
Health	O
Report	O
about:home	B-Protocol
Shows	O
the	O
Firefox	B-Application
4	O
default	O
home	O
page	O
about:jetpack	O
Shows	O
an	O
interface	O
for	O
viewing	O
and	O
setting	O
the	O
JetPack	B-Application
extension	I-Application
about:licence	O
The	O
equivalent	O
of	O
about:license	O
in	O
the	O
British	O
English	O
localizations	O
of	O
Firefox	B-Application
.	O
</s>
<s>
Not	O
available	O
since	O
Firefox	B-Application
4	O
.	O
about:license	O
Shows	O
the	O
Mozilla	B-License
Public	I-License
License	I-License
(	O
and	O
the	O
Netscape	B-Application
Public	I-Application
License	I-Application
)	O
for	O
the	O
piece	O
of	O
software	O
(	O
Gecko	B-Language
1.8	I-Language
+	O
)	O
about:logo	O
Shows	O
the	O
logo	O
used	O
on	O
the	O
about	B-Protocol
:	I-Protocol
screen	O
about:memory	O
Shows	O
memory	O
usage	O
(	O
Firefox	B-Application
3.6	O
+	O
)	O
about:mozilla	B-Application
Easter	O
egg	O
,	O
shows	O
a	O
verse	O
from	O
The	B-Application
Book	I-Application
of	I-Application
Mozilla	I-Application
about:neterror	O
Shows	O
the	O
error	O
page	O
used	O
when	O
the	O
browser	B-Application
could	O
not	O
access	O
the	O
requested	O
pathabout:newaddonThis	O
URI	B-Protocol
is	O
not	O
registered	O
.	O
</s>
<s>
However	O
,	O
when	O
the	O
user	O
tries	O
to	O
sideload	B-Protocol
an	O
add-on	O
,	O
a	O
dialog	O
box	O
bearing	O
this	O
URI	B-Protocol
appears	O
.	O
</s>
<s>
about:newtab	O
Shows	O
a	O
grid	O
of	O
favourite	O
and	O
most-visited	O
websites	O
(	O
Firefox	B-Application
13+	O
)	O
about:permissionsShows	O
permissions	O
for	O
all	O
sites	O
on	O
Firefox	B-Application
6.0a1	O
about:plugins	O
Shows	O
installed	O
,	O
currently	O
enabled	O
plug-ins	O
about:preferences	O
Shows	O
the	O
new	O
preferences	O
page	O
about:privatebrowsing	O
Can	O
be	O
used	O
to	O
switch	O
to	O
private	O
browsing	O
mode	O
.	O
</s>
<s>
It	O
shows	O
a	O
message	O
indicating	O
that	O
Firefox	B-Application
will	O
not	O
remember	O
any	O
history	O
for	O
the	O
current	O
session	O
.	O
</s>
<s>
Note	O
:	O
It	O
does	O
not	O
show	O
URI	B-Protocol
on	O
the	O
address	O
bar	O
about:reader	O
?	O
url	O
=	O
Opens	O
the	O
specified	O
URL	O
in	O
Reader	O
Mode	O
.	O
</s>
<s>
about:rights	O
Shows	O
licensing	O
information	O
about:robots	B-Protocol
Easter	O
egg	O
,	O
beginning	O
with	O
March	O
8	O
,	O
2008	O
trunk	O
builds	O
.	O
</s>
<s>
about:startpage	O
In	O
Ubuntu	O
,	O
shows	O
the	O
Ubuntu	O
start	O
page	O
with	O
the	O
current	O
search	O
engine	O
(	O
if	O
the	O
"	O
Ubuntu	O
Firefox	B-Application
Modifications	O
–	O
ubufox	O
"	O
add-on	O
is	O
installed	O
)	O
about:support	O
Shows	O
troubleshooting	O
information	O
(	O
Firefox	B-Application
3.6	O
+	O
,	O
SeaMonkey	B-Language
2.1	O
+	O
)	O
about:sync-tabs	O
Shows	O
list	O
of	O
tabs	O
from	O
other	O
computers	O
.	O
</s>
<s>
In	O
Opera	B-Application
,	O
about	B-Protocol
:	I-Protocol
is	O
an	O
alias	O
for	O
the	O
opera	B-Protocol
:	I-Protocol
scheme	O
;	O
therefore	O
all	O
these	O
URIs	B-Protocol
also	O
work	O
with	O
about	O
prefixed	O
.	O
</s>
<s>
User	O
JavaScript	B-Language
is	O
enabled	O
for	O
all	O
URIs	B-Protocol
in	O
the	O
about	B-Protocol
:	I-Protocol
or	O
opera	B-Protocol
:	I-Protocol
schemes	O
as	O
a	O
security	O
feature	O
.	O
</s>
<s>
These	O
pages	O
can	O
,	O
however	O
,	O
be	O
styled	O
using	O
local	O
stylesheets	B-Language
.	O
</s>
<s>
None	O
of	O
these	O
functions	O
,	O
except	O
the	O
opera:about	O
combination	O
,	O
work	O
in	O
the	O
Nintendo	B-Application
DS	I-Application
Browser	I-Application
,	O
which	O
is	O
an	O
Opera	B-Application
derivative	O
.	O
</s>
<s>
+	O
Opera-specific	O
"	O
about	B-Protocol
:	I-Protocol
"	O
URIs	B-Protocol
URIs	B-Protocol
Purpose	O
opera:blank	O
Maps	O
to	O
about:blank	O
opera:about	O
Provides	O
info	O
about	O
the	O
browser	B-Application
and	O
the	O
configured	O
paths	O
about:opera	O
Maps	O
to	O
opera:about	O
opera:cache	O
Shows	O
the	O
content	O
of	O
the	O
cache	O
opera:config	O
Shows	O
a	O
page	O
that	O
allows	O
changing	O
of	O
numerous	O
browser	B-Application
preferences	O
,	O
many	O
of	O
which	O
cannot	O
be	O
accessed	O
through	O
the	O
normal	O
Preferences	O
window	O
(	O
Opera	B-Application
9.0	O
and	O
newer	O
)	O
opera:drives	O
Shows	O
the	O
local	O
drives	O
of	O
the	O
host	O
system	O
opera:history	O
Shows	O
the	O
content	O
of	O
the	O
browser	B-Application
history	O
opera:historysearch	O
Shows	O
the	O
start	O
page	O
of	O
internal	O
search	O
engine	O
for	O
the	O
browser	B-Application
history	O
(	O
Opera	B-Application
9.5	O
and	O
newer	O
)	O
opera:plugins	O
Shows	O
installed	O
plug-ins	O
.	O
</s>
<s>
Opera	B-Application
11	O
and	O
newer	O
allow	O
individual	O
plug-ins	O
to	O
be	O
disabled	O
from	O
this	O
page	O
.	O
</s>
<s>
opera:button	O
Defines	O
a	O
custom	O
button	O
as	O
a	O
set	O
of	O
Opera	B-Application
actions	O
.	O
</s>
<s>
opera:help	O
Shortcut	O
to	O
the	O
help	O
directory	O
.	O
</s>
<s>
Internet	B-Application
Explorer	I-Application
about	O
URIs	B-Protocol
are	O
configurable	O
in	O
Windows	B-Application
.	O
</s>
<s>
It	O
is	O
therefore	O
possible	O
that	O
some	O
of	O
the	O
listed	O
URIs	B-Protocol
will	O
not	O
work	O
on	O
a	O
particular	O
computer	O
.	O
</s>
<s>
For	O
example	O
,	O
"	O
about:mozilla	B-Application
"	O
was	O
removed	O
in	O
SP2	O
(	O
although	O
the	O
page	O
can	O
still	O
be	O
found	O
at	O
"	O
res://mshtml.dll/about.moz	O
"	O
)	O
.	O
</s>
<s>
These	O
about	O
URIs	B-Protocol
are	O
sometimes	O
used	O
for	O
spyware	O
and	O
adware	O
,	O
most	O
notably	O
in	O
CoolWebSearch	O
,	O
which	O
made	O
about:blank	O
display	O
advertisements	O
.	O
</s>
<s>
Any	O
about	O
URI	B-Protocol
that	O
is	O
not	O
recognized	O
by	O
Internet	B-Application
Explorer	I-Application
redirects	O
to	O
a	O
page	O
saying	O
"	O
Navigation	O
to	O
the	O
webpage	O
was	O
canceled.	O
"	O
</s>
<s>
+	O
Internet	O
Explorer-specific	O
"	O
about	B-Protocol
:	I-Protocol
"	O
URIs	B-Protocol
URIPurposeSupported	O
versions	O
about:homeDisplays	O
the	O
user	O
's	O
home	O
page.6	O
,	O
7	O
,	O
9	O
,	O
10	O
,	O
11	O
(	O
not	O
8	O
)	O
about:desktopitemnavigationfailureDisplays	O
the	O
"	O
navigation	O
cancelled	O
"	O
page.6	O
–	O
8	O
about:navigationcanceled	O
about:navigationfailure	O
about:noadd-onsAppears	O
when	O
add-ons	O
are	O
disabled	O
to	O
notify	O
the	O
users	O
of	O
a	O
change	O
in	O
their	O
web	O
browsing	O
experience.7	O
–	O
11	O
about:noadd-onsinfoContains	O
information	O
about	O
add-ons	O
and	O
what	O
they	O
do.7	O
–	O
11	O
about:offlineinformationInforms	O
the	O
user	O
that	O
the	O
current	O
page	O
cannot	O
be	O
viewed	O
offline	O
.	O
</s>
<s>
Internet	B-Application
Explorer	I-Application
9	I-Application
and	O
later	O
do	O
not	O
support	O
offline	O
browsing.6	O
–	O
8	O
about:postnotcachedInforms	O
the	O
user	O
that	O
the	O
current	O
page	O
needs	O
to	O
refresh	O
and	O
any	O
information	O
entered	O
in	O
a	O
form	O
will	O
have	O
to	O
be	O
re-posted.6	O
–	O
11	O
about:securityriskInforms	O
the	O
user	O
not	O
to	O
browse	O
with	O
the	O
current	O
security	O
settings	O
because	O
they	O
may	O
be	O
harmful	O
to	O
the	O
computer.6	O
–	O
11	O
about:tabsInforms	O
the	O
user	O
about	O
tabbed	O
browsing	O
.	O
</s>
<s>
Internet	B-Application
Explorer	I-Application
shows	O
this	O
page	O
upon	O
creating	O
a	O
new	O
tab	O
if	O
the	O
"	O
Open	O
home	O
page	O
for	O
new	O
tabs	O
instead	O
of	O
a	O
blank	O
page	O
"	O
setting	O
is	O
enabled.7	O
–	O
11	O
about:inprivateAppears	O
when	O
the	O
use	O
initiates	O
InPrivate	O
Browsing	O
;	O
contains	O
information	O
about	O
this	O
feature.9	O
–	O
11	O
about:compatDisplays	O
a	O
table	O
of	O
sites	O
and	O
the	O
document	O
rendering	O
emulation	O
mode	O
configured	O
for	O
maximum	O
backward	O
compatibility.11	O
about:newsfeedDisplays	O
Internet	B-Application
Explorer	I-Application
11	O
's	O
signature	O
start	O
page	O
.	O
</s>
<s>
The	O
following	O
applies	O
to	O
Microsoft	B-Application
Edge	I-Application
version	O
20	O
through	O
44	O
,	O
which	O
Microsoft	O
dubs	O
"	O
the	O
legacy	O
Edge.	O
"	O
</s>
<s>
For	O
newer	O
versions	O
,	O
see	O
the	O
Chromium	B-Language
section	O
.	O
</s>
<s>
+	O
Microsoft	O
Edge-specific	O
"	O
about	B-Protocol
:	I-Protocol
"	O
URIs	B-Protocol
URI	B-Protocol
Purpose	O
about:home	B-Protocol
Shows	O
the	O
content	O
that	O
would	O
be	O
shown	O
if	O
the	O
home	O
button	O
were	O
pressed	O
about:flags	O
Displays	O
a	O
list	O
of	O
Developer	O
Setting	O
and	O
Experimental	O
features	O
about:start	O
Shows	O
the	O
customizable	O
(	O
default	O
)	O
start	O
page	O
.	O
</s>
<s>
about:config	O
Redirects	O
to	O
about:flags	O
about:tabs	B-Protocol
Shows	O
the	O
(	O
default	O
)	O
new	O
tab	O
page	O
.	O
</s>
<s>
about:compat	O
Shows	O
the	O
Enterprise	O
Mode	O
list	O
(	O
if	O
configured	O
)	O
about:edge	O
Shows	O
the	O
Edge	B-Application
logo	O
.	O
</s>
<s>
When	O
GNOME	B-Language
Web	I-Language
(	O
formerly	O
Epiphany	B-Language
)	O
used	O
Gecko	B-Language
as	O
its	O
layout	O
engine	O
,	O
all	O
Firefox-specific	O
about	B-Protocol
:	I-Protocol
URIs	B-Protocol
worked	O
in	O
it	O
.	O
</s>
<s>
After	O
the	O
adoption	O
of	O
WebKit	B-Language
as	O
its	O
layout	O
engine	O
,	O
only	O
the	O
following	O
URIs	B-Protocol
are	O
supported	O
.	O
</s>
<s>
+	O
GNOME	O
Web-specific	O
"	O
about	B-Protocol
:	I-Protocol
"	O
URIs	B-Protocol
URI	B-Protocol
Purpose	O
about:plugins	O
Shows	O
installed	O
plug-ins	O
.	O
</s>
<s>
about:epiphany	O
Displays	O
the	O
following	O
message	O
:	O
</s>
<s>
about:web	O
Displays	O
the	O
browser	B-Application
and	O
its	O
engine	O
information	O
,	O
same	O
as	O
about:about:incognitoDisplays	O
information	O
about	O
incognito	O
mode	O
.	O
</s>
<s>
The	O
about	B-Protocol
:	I-Protocol
URL	I-Protocol
originated	O
in	O
and	O
has	O
existed	O
in	O
all	O
versions	O
of	O
Netscape	B-Protocol
browsers	B-Application
.	O
</s>
<s>
Older	O
versions	O
of	O
the	O
Netscape	B-Protocol
browser	B-Application
have	O
an	O
about:people	O
URI	B-Protocol
that	O
was	O
similar	O
to	O
about:credits	O
above	O
,	O
but	O
it	O
would	O
redirect	O
to	O
Netscape	B-Protocol
's	O
active	O
employee	O
listing	O
.	O
</s>
<s>
In	O
addition	O
,	O
about:username	O
,	O
where	O
username	O
is	O
the	O
username	O
of	O
a	O
Netscape	B-Protocol
employee	O
,	O
would	O
redirect	O
to	O
the	O
Netscape	B-Protocol
homepage	O
of	O
the	O
employee	O
specified	O
.	O
</s>
<s>
For	O
example	O
,	O
about:jwz	O
would	O
redirect	O
to	O
http://people.netscape.com/jwz/	O
(	O
not	O
an	O
active	O
link	O
)	O
.	O
</s>
<s>
Many	O
other	O
about	B-Protocol
:	I-Protocol
easter	O
eggs	O
existed	O
,	O
including	O
the	O
famous	O
about:mozilla	B-Application
,	O
and	O
other	O
less	O
known	O
ones	O
that	O
showed	O
pictures	O
of	O
the	O
Netscape	B-Protocol
mascot	O
Mozilla	B-Language
in	O
various	O
foreign	O
garb	O
,	O
such	O
as	O
about:deutsch	O
showing	O
Mozilla	B-Language
in	O
Lederhosen	O
.	O
</s>
<s>
Some	O
versions	O
of	O
Netscape	B-Protocol
would	O
display	O
the	O
browser	B-Application
history	O
for	O
the	O
about:global	O
URI	B-Protocol
.	O
</s>
<s>
In	O
Konqueror	B-Application
,	O
any	O
about	O
URI	B-Protocol
except	O
about:blank	O
and	O
about:plugins	O
redirects	O
to	O
about:konqueror	O
,	O
which	O
shows	O
a	O
friendly	O
‘	O
start’	O
and	O
navigation	O
page	O
.	O
</s>
<s>
In	O
Internet	B-Protocol
Explorer	I-Protocol
for	I-Protocol
Mac	I-Protocol
5	O
was	O
an	O
offline	O
Easter	O
egg	O
,	O
accessible	O
by	O
typing	O
‘	O
about:tasman	O
’	O
,	O
showing	O
the	O
Acid1	O
test	O
with	O
the	O
text	O
replaced	O
by	O
the	O
names	O
of	O
the	O
developers	O
.	O
</s>
<s>
Safari	B-Application
only	O
recognizes	O
about:blank	O
.	O
</s>
<s>
Microsoft	B-Application
Outlook	I-Application
supports	O
an	O
additional	O
outlook:today	O
URI	B-Protocol
,	O
which	O
shows	O
the	O
Outlook	O
Today	O
Screen	O
.	O
</s>
<s>
This	O
screen	O
shows	O
messages	O
,	O
tasks	O
and	O
appointments	O
;	O
it	O
is	O
also	O
accessible	O
from	O
Internet	B-Application
Explorer	I-Application
.	O
</s>
<s>
Outlook	O
recognizes	O
about:blank	O
too	O
,	O
but	O
no	O
other	O
"	O
about	B-Protocol
:	I-Protocol
"	O
URIs	B-Protocol
.	O
</s>
