"CL" is a Google-ism for a code change ("change list"). What we'd normally refer to as a pull request I suppose. Googlers like to think the whole world is in on their lingo, but CL is a very unusual acronym outside the Googlosphere.

So they are seriously saying that Google developers on average went from about 70 PRs per year to less than 10 PRs per year when working from home? That seems such an absurdly large decrease that it's hard to believe.