A report in L'Expansion claims that Google has finalized the acquisition of FlexyCore, an optimization company based in Rennes, France, for 16.9 million Euros (just over $23 million USD). Google confirmed the sale to GigaOM, but did not comment on the price or purpose. The French website says that Google has been processing the acquisition for over a year and finally closed the deal earlier this month.
FlexyCore is a five-year-old company founded by Gilbert Cabillic, a former head researcher for Texas Instruments. Their primary product was optimizing Android for carriers and manufacturers. The company also tried its hand at sales directly to consumers through the DroidBooster app, which seems to have been removed from the Play Store some time ago. I haven't been able to find any quantified information about FlexyCore's Android improvements, but a Google France representative said that the team has already been integrated into Google's mobile arm, so there must have been something substantial in there.
The acquisition was a secret for the better part of a year and was only revealed due to some internal restructuring in Google France. While it's unlikely that end users will ever be able to see direct evidence of this corporate move, some of FlexyCore's expertise may already have been applied to the later builds of Android.