It seems open-vm-tools-dkms was deprecated in Debian 9 (Stretch) and is no longer available in Debian 10 (Buster).
What does this mean — is the functionality obsolete or has it moved to some other package?
It seems open-vm-tools-dkms was deprecated in Debian 9 (Stretch) and is no longer available in Debian 10 (Buster).
What does this mean — is the functionality obsolete or has it moved to some other package?
The package provided the vmxnet driver, which is obsolete and replaced by the vmxnet3 driver which is part of the kernel. This is alluded to in the package description in Stretch:
This package provides the source code for the vmxnet module, which was superseded by vmxnet3. You should only install this package if you know that you need the legacy vnxnet module. Kernel source or headers are required to compile it using DKMS.
vmxnet3 is provided in the kernel packages in Debian, you don’t need a separate DKMS package to get it.