"We're announcing a partnership with GitHub where you're going to have push-button deployments," Greene told CNBC on Tuesday at the company's Next cloud conference in San Francisco.
"Obviously, we do a lot on GitHub, Google does, because of all our open-source. So they're a great company, and they're just a great service for everybody, and I'm sort of sad they're at Microsoft. We'll see what happens. Hopefully, you know, they won't favor Microsoft, but, you know, that's where it is."
The remarks from Google Cloud CEO Diane Greene reflects how Google and so many other companies have depended on GitHub for hosting code -- and will continue to regardless of their competitive relationship with new owner Microsoft.
In the context of open-source software, Microsoft CEO Satya Nadella has said that the world should judge the company by recent and upcoming decisions, not by things that have happened long ago. Microsoft once was antagonistic toward open-source software, but under Nadella's leadership has taken a softer stance. The company has embraced Linux on Azure and even with its SQL Server database software, and has open-sourced more of its own software.
CNBC previously reported that Google was looking at buying GitHub, but Greene wouldn't confirm the report.
"I think the only thing I've said is that I wouldn't have minded having them," said Greene.
Google evaluates companies of all sizes for acquisitions, she said.
"I think, as a general way of how we think about M&A, if there is a mid-sized deal, we would look pretty hard at that," said Greene, who is also a member of the board at Google's parent company, Alphabet.
"We do a lot of sort of deals under $10 million and in the tens of millions. And then, I mean, we actually do pretty deep due diligence on anything, because it's a distraction to buy another company, and you want it to be super successful and a good experience for everybody, and you don't want anybody wasting their time."
In an interview earlier this year, Greene said that people were "underestimating" Google's cloud business. On the same day, Google also announced that the company books more than $1 billion in revenue per quarter from cloud products, including its G Suite of productivity apps and its cloud infrastructure.
But in the past two quarters, Google did not provide updates on the figure.
Greene wouldn't talk about financial growth since the billion-dollar statement, and she said Google wouldn't be providing regular updates on cloud revenue.
"Why would they need to know that?" she said.
Rather than using raw revenue numbers, Greene said people should seek to compare Google with other cloud service sellers by talking with customers, trying out various services and considering their plans for the future. Revenue doesn't necessarily align with quality of products, she said.
"I'm not saying we're not the fastest. We may very well be. I just can't say," she said.
"But looking at that kind of stuff [revenue figures], those are kind of lagging indicators, as opposed to what's real and what can I use and how can I drive my business. And how do they work with me."