Variable groups have been introduced in TFS/VSTS to address this need.
These are shared variables at the team project level, and can be used in build or release definitions. The ability to refer to variable groups from release definitions is complete and is now available in TFS 2017 and VSTS. The ability to refer to variables groups from build definitions is planned in the next 3 months.
1,518 votes62 comments · Visual Studio IDE » Version Control (Git/TFVC) · Flag idea as inappropriate… · Admin →
We are excited to let you know that we are working on this suggestion. We expect this feature to be released by the end of the year. Not only will you be able to commit to submodules, but you will also be able to view the file history and blame within a submodule.
However, VS will not yet have “full” submodule support; you will only be able to have one Git repo open per VS instance. Therefore, working between a submodule and the parent repo will not be seamless. To help us prioritize further submodule features, please open new UserVoice items.
Program ManagerDevSlick commented
How is this not already supported?
Thank you for using Visual Studio and for your commitment to improving it. We are currently evaluating whether we will be able to include this into the product.