<s>
SponsorBlock	B-Operating_System
is	O
a	O
free	B-License
and	I-License
open-source	I-License
browser	B-Protocol
extension	I-Protocol
designed	O
to	O
skip	O
(	O
block	O
)	O
sponsorship	O
segments	O
in	O
YouTube	B-General_Concept
videos	I-General_Concept
.	O
</s>
<s>
The	O
extension	O
is	O
a	O
recommended	O
extension	O
on	O
Firefox	B-Application
's	O
add-on	O
store	O
.	O
</s>
<s>
,	O
the	O
extension	O
has	O
284,907	O
users	O
on	O
Firefox	B-Application
and	O
over	O
900,000	O
users	O
on	O
Google	B-Application
Chrome	I-Application
.	O
</s>
<s>
SponsorBlock	B-Operating_System
segment	O
retrieval	O
API	O
observes	O
20-anonymity	O
.	O
</s>
<s>
Initially	O
,	O
SponsorBlock	B-Operating_System
could	O
only	O
be	O
used	O
to	O
submit	O
and	O
skip	O
sponsorship	O
segments	O
,	O
but	O
support	O
for	O
multiple	O
segment	O
categories	O
(	O
such	O
as	O
self-promotion	O
or	O
intermission	O
segments	O
)	O
was	O
added	O
in	O
June	O
2020	O
.	O
</s>
<s>
The	O
SponsorBlock	B-Operating_System
can	O
be	O
used	O
as	O
browser	B-Protocol
extension	I-Protocol
,	O
on	O
Chromium	O
,	O
Safari	O
,	O
and	O
can	O
also	O
be	O
used	O
on	O
Android	O
,	O
and	O
iOS	O
.	O
</s>
<s>
The	O
extension	O
is	O
a	O
recommended	O
extension	O
on	O
Firefox	B-Application
and	O
,	O
,	O
is	O
the	O
highest-rated	O
recommended	O
extension	O
listed	O
.	O
</s>
