The extension will automatically activate when you open a .dmd file.
Example
# This is a comment
# Simple module without version
dmffs
make_dmffs
# Module with specific version
driver@1.0
# Include another dependencies file
$include http://repo.com/other.dmd
# Change the manifest source
$from https://repo.com/manifest.dmm
# Modules after this will use the new manifest
spi@1.0
i2c@2.0
Language Support
Comments: Lines starting with # are treated as comments
Module entries: Module names with optional @version suffix
Include directive: $include <url> to include other .dmd files
From directive: $from <manifest_url> to change the manifest source