Do you mean across all of Microsoft? Different teams have different structures. Speaking only for TFS and VSTS, we have a single repo containing the code for both, a handful of "adjunct" repos containing tools like GVFS, a repo for the documentation [1], and a bunch of open source repos for the build and release agent [2], agent tasks [3], API samples [4], and probably more I don't know about.
Do you mean across all of Microsoft? Different teams have different structures. Speaking only for TFS and VSTS, we have a single repo containing the code for both, a handful of "adjunct" repos containing tools like GVFS, a repo for the documentation [1], and a bunch of open source repos for the build and release agent [2], agent tasks [3], API samples [4], and probably more I don't know about.
[1] https://www.visualstudio.com/docs
[2] https://github.com/microsoft/vsts-agent
[3] https://github.com/Microsoft/vsts-tasks
[4] https://github.com/Microsoft/vsts-dotnet-samples