Most of the version control system (VCS) fields types are common to both `source-repository` and `source-repository-package` stanzas.

Field Name | source-repository (head|this) | source-repository-package
--- | --- | ---
type | [x] | [x]
location | [x] | [x]
branch | [x] | [x]
tag | [x] | [x]
subdir | [x] (0 or 1) | [x] (0 or 1 for each dependency)
module (CVS only) | [x] | [_]
post-checkout-command | [_] | [x]