--
* `0` or `false` - Disables the target.
* `1` or `true` - Writes to `STDERR`.
* `[2-9]` - Writes to the already opened file descriptor.
* `<absolute-pathname>` - Writes to the file in append mode.
* `af_unix:[<socket_type>:]<absolute-pathname>` - Write to a
Unix DomainSocket (on platforms that support them).  Socket
type can be either `stream` or `dgram`; if omitted Git will
try both.
--