Opera Software on Friday released a development build of its Opera browser to the public to prove that it has code that scores 100 out of a possible 100 on the Acid3 Web standards test.

In a follow-up to an announcement earlier last week, Opera posted downloads for Windows and Linux users of what it dubbed "WinGogi desktop" to the Labs page of its site.

"This is not a regular Opera desktop build, but ... the Windows version of the reference builds that we use internally for testing Opera's platform-independent Core," said Lars Erik Bolstad, the head of Opera's core technology team, in a post to the company's blog.

"'Desktop' means it is compiled with the same feature set as our regular desktop browser," Bolstad continued. "Still, we do not recommend using this build for regular Web surfing as it lacks some of the security-related features found in our regular desktop versions."

Opera said last Wednesday that it was the first browser maker to declare that it had a working version that scored 100 out of 100 on Acid3. That test, which was finalised earlier this month by the Web Standards Project, checks how closely a browser follows certain standards - particularly specifications for Web 2.0 applications.

Later that day, developers working on the open-source WebKit Project, which provides the engine that powers Apple's Safari, matched Opera's claim, but also posted Mac OS X and Windows versions for downloading so users could try it against Acid3 for themselves.

Techworld's sister publication, Computerworld downloaded the Windows version of the Opera build and confirmed that it scored 100 on Acid3.

Opera's Bolstad said his developers have more work to do. "There are at least two subtests where we feel we need to improve the performance in order to achieve a perfect pass on current hardware," he said.

Mozilla, which is in the final stages of work on Firefox 3.0, has said it won't divert resources to rework its browser for a higher Acid3 score. Microsoft, meanwhile, only recently made a version of Internet Explorer 8 available that passed the previous standards test, Acid2.