Opera Software has ‘lost’ approximately 90 employees, some of them straight-up veterans of the Oslo, Norway-based browser maker, Digi.no duly reported earlier today (in Norwegian).

The downsizing was actually announced by Opera itself in its Q4 2012 earnings report last week. In the report, the company specified that it ended the last quarter of 2012 with 840 instead of 931 full-time employees due to a ‘restructuring’ effort.

According to the same report, the costs of the restructuring mounted to $7.8 million in Q4 2012 alone.

The shrinking of Opera’s workforce on itself is noteworthy – as it amounts to approximately 10 percent of its total employee base – even though the company saw net job growth of 73 employees over the course of 2012 with the restructuring taken into account.

However, contrary to what Digi.no and other reports might suggest, the 90-something employees that left Opera weren’t all developers that were unilaterally canned. Rather, some of the jobs at the Norwegian browser software company had simply become obsolete over the course of 2012 because of the switch from its proprietary rendering engine Presto to the open-source WebKit project.

Most people left between the months of October and November 2012.

The Next Web talked to Opera Software CEO Lars Boilesen this afternoon, and he noted that a lot of the people that stopped working for the company in the second half of last year voluntarily decided to leave due to the switch to WebKit, after being offered severance packages.

Others, some of they key engineers, were however reassigned to other product-specific roles within the company, Boilesen added.

Not all of those who left served in technical roles either, as some of the people that are no longer with the Opera Software actually worked in marketing and sales and a number of other departments. Boilesen noted that the company has actively helped many of them find new jobs within Norway’s IT industry.

In fact, of the 90 people who left Opera, only about half were developers.

Boilesen also said Opera has never employed as many engineers in its smartphone, tablet and desktop browser product divisions throughout its now 18-year history, asserting that they’re now in super shape.

By no longer dedicating so many resources to developing their own rendering engine but instead contributing to the WebKit community, he says Opera can now focus more on improving existing and building new products.

And, as Boilesen noted in a follow-up interview to Digi.no, the expectation is for Opera to keep hiring and become bigger than ever this year. We’ll be watching its earnings reports closely.

Opera Software recently announced that its range of Web browsers is now being used by 300 million people each month.

The company also just announced its acquisition of Skyfire, a mobile video optimization specialist and fellow mobile browser maker, for $155 million.

The company is expected to make more, product-focused announcements next week at the Mobile World Congress in Barcelona.