Microsoft maintains the entire Windows source tree in Git now and has made some really interesting contributions to git where it comes to very large projects, though I don't know about the penetration throughout other dev groups. They also own Github now obviously.

I was just looking at Microsoft's git VFS (https://github.com/microsoft/VFSForGit), which is deprecated and now points to Scalar (https://github.com/microsoft/scalar), which is also deprecated I think? What's Microsoft's story with git for large repos now? Is there still a virtual file system involved at all?

Microsoft is trying to get away from needing a VFS. Scalar eventually accomplished that by combining some enhancements that had been added to git since they originally designed the Git VFS, and plus some new features that only live in scalar.

The long term plan is for Scalar to either go away completely, or possibly just be a simple front end for setting up a repository to use certain optional git features.

They actually have a version of scalar in official git's contrib folder, and they are very actively working with the core git team to convert the relevant features into core git features in whatever way the core git team is happy with.

But of course the present situation is certainly confusing, and does not seem to be well documented. I've only picked up on some of this from reading the git mailing lists, and have no idea how to actually use scalar.

As Scalar README says, is it merged to microsoft/git ?

That doesn't really answer my questions though. What exactly does microsoft/git do that makes monorepos better? The readme doesn't answer. They have a branch called vfs but the readme doesn't mention virtual filesystems at all.

was this before or after the github acquisition? I figure if they were going to spend the money for github they probably intend for git to have a bigger role

Microsoft started the Windows transition to git sometime before Github acquisition as a part of a company-wide effort to move to VSTS/Azure DevOps Repos internal dogfooding. The choice there was between the zombie ghost of TFS source control or git, so you can possibly imagine some of the reasons why they chose to put a lot of time/effort into making git work for themselves. The subsequent acquisition of Github seems to have made them even happier at the switch to git.

long before

Apple has traditionally left absolutely everything up to individual teams.

Everything I touched at apple while I was there was internal GitHub.

A lot of teams use BitBucket. The PIE GitHub sees most of its use inside of certain orgs.

MS uses git with Azure DevOps, at least for all the repos I'm familiar with.

It seems they used their own proprietary solution before starting to support git: https://en.wikipedia.org/wiki/Azure_DevOps_Server#Source_con...

Lots of Git projects. Internal development has centered around using Git, even for WebKit, for several years.