vdm is an alternative to e.g. Git Submodules for managing arbitrary external dependencies for the same reasons, in a more sane way. Unlike some other tools that try to solve this problem, vdm is language-agnostic, and can be used for any purpose that you would need remote development resources.
vdm can be used for many different purposes, but most commonly as a way to track external dependencies that your own code might need, but that you don't have a language-native way to specify. Some examples might be:
You're building & testing a backend application and need to test serving frontend code from it, and your team has that frontend code in another repository.
vdm can be installed from its GitHub Releases page. There is a zipped binary for major platforms & architectures, and those are indicated in the Asset file name. For example, if you have an M2 macOS laptop, you would download the vdm_darwin-arm64.tar.gz file, and extract it to somewhere on your $PATH.
To get started, you'll need a vdm spec file, which is just a YAML (or JSON) file specifying all your external dependencies along with (usually) their revisions & where you want them to live on your filesystem: