<s>
Sigil	B-Operating_System
is	O
free	B-Application
,	O
open-source	B-Application
editing	O
software	O
for	O
e-books	O
in	O
the	O
EPUB	O
format	O
.	O
</s>
<s>
As	O
a	O
cross-platform	B-Operating_System
application	O
,	O
Sigil	B-Operating_System
is	O
distributed	O
for	O
the	O
Windows	B-Application
,	O
macOS	B-Application
,	O
Haiku	B-Language
and	O
Linux	B-Application
platforms	O
under	O
the	O
GNU	B-License
GPL	I-License
license	I-License
.	O
</s>
<s>
Sigil	B-Operating_System
supports	O
code-based	O
editing	O
of	O
EPUB	O
files	O
,	O
as	O
well	O
as	O
the	O
import	O
of	O
HTML	B-Language
and	O
plain	B-General_Concept
text	I-General_Concept
files	O
.	O
</s>
<s>
A	O
companion	O
application	O
,	O
PageEdit	B-Operating_System
,	O
allows	O
WYSIWYG	B-Application
editing	O
of	O
EPUB	O
files	O
.	O
</s>
<s>
Sigil	B-Operating_System
has	O
been	O
developed	O
by	O
Strahinja	O
Val	O
Marković	O
and	O
others	O
since	O
2009	O
.	O
</s>
<s>
In	O
June	O
2015	O
development	O
of	O
Sigil	B-Operating_System
was	O
taken	O
over	O
by	O
Kevin	O
Hendricks	O
and	O
Doug	O
Massay	O
.	O
</s>
<s>
Sigil	B-Operating_System
's	O
features	O
include	O
:	O
</s>
<s>
Sigil	B-Operating_System
has	O
full	O
EPUB2	O
specifications	O
support	O
,	O
but	O
only	O
limited	O
EPUB3	O
support	O
.	O
</s>
<s>
Since	O
version	O
0.9.3	O
of	O
January	O
2016	O
,	O
the	O
developers	O
have	O
been	O
focusing	O
on	O
"	O
improving	O
Sigil	B-Operating_System
’s	O
ability	O
to	O
work	O
with	O
and	O
generate	O
epub3	O
ebooks	O
without	O
losing	O
any	O
of	O
its	O
epub2	O
capabilities	O
"	O
.	O
</s>
<s>
WYSIWYG	B-Application
editing	O
in	O
book	O
view	O
was	O
discontinued	O
in	O
2019	O
and	O
moved	O
to	O
a	O
separate	O
application	O
,	O
PageEdit	B-Operating_System
.	O
</s>
