You can read about the VS solution format here: https://learn.microsoft.com/en-us/visualstudio/extensibility...

As you can see it's quite complicated. The contents of go.work is literally

    mod1/
    mod2/

Also, the go.work file is meant to be your local workspace. If mod1 and mod2 have dependencies between each other, they should declare them explicitly and pull them in from the remote in most cases. The go.work file is only when you want to work on both modules locally. Meaning you don't check in go.work to your github repository in most cases.