Mozilla and Yahoo are suing each over Firefox's default search engine

In yet another tech battle of the titans, Mozilla and Oath are suing each other over a contract that set Yahoo as the default search engine for Mozilla's Firefox browser.

The pair originally signed a deal in 2014 that would have made Yahoo the default search engine for Firefox through 2019. But Mozilla has decided to exit the deal and take up with Google.

Oath, the Verizon-owned company that resulted from the merger of Yahoo and AOL in 2017, is accusing Mozilla of improperly walking away from their deal, and formally filed a complaint against Mozilla for "breach of contract" and "breach of covenant of good faith and fair dealing."

You can read a few more details in this heavily redacted version [PDF] of Oath's complaint that was posted online by Mozilla.

Mashable has reached out to Oath for further comment.

On Tuesday, Mozilla responded with a suit of their own against Oath, saying they had a perfectly good reason for walking away.

They posted a full statement online, saying, in part:

We recently exercised our contractual right to terminate our agreement with Yahoo based on a number of factors including doing what’s best for our brand, our effort to provide quality web search, and the broader content experience for our users.

To Mozilla, Yahoo being acquired by Oath was a bad thing that would negatively affect Firefox which would trigger a clause that in the contract that would allow Mozilla to back out of the contract but maintain "post-termination rights" that would force Yahoo to keep paying up through the end of the contract.

Immediately following Yahoo’s acquisition, we undertook a lengthy, multi-month process to seek assurances from Yahoo and its acquirers with respect to those factors. When it became clear that continuing to use Yahoo as our default search provider would have a negative impact on all of the above, we exercised our contractual right to terminate the agreement and entered into an agreement with another provider.

Obviously, Oath doesn't want to have to continue paying Mozilla after they've ditched Yahoo and taken up with a competitor. As Engadget notes, the deal was signed under former Yahoo CEO Marissa Mayer, who gave Mozilla the very friendly terms.

So, now, yet another tech-related dispute will be settled as it should be: in the Thunderdome in a court of law.