When fetching sources for a Git-site-defined package, releng-tool will
keep a project's Git repository inside a cache folder and use the project's
build directory as the Git work-tree. When extracting a given revision for
a project, releng-tool will also attempt to setup a
.git file to point to
the cache directory, if users want to perform Git-related commands
(typically, only for unique development/testing scenarios).
In the case where developers want a complete copy of the Git repository in
the build folder instead of a pointer to the cache, the
releng.git.replicate_cache quirk can be enabled to force releng-tool to
copy over the Git repository when a package is extracted.
releng-tool --quirk releng.git.replicate_cache