git/Documentation/pull-fetch-param.txt

<repository>::
	The "remote" repository that is the source of a fetch
	or pull operation.  This parameter can be either a URL
	(see the section <<URLS,GIT URLS>> below) or the name
	of a remote (see the section <<REMOTES,REMOTES>> below).

ifndef::git-pull[]
<group>::
	A name referring to a list of repositories as the value
	of remotes.<group> in the configuration file.
	(See linkgit:git-config[1]).
endif::git-pull[]

<refspec>::
	Specifies which refs to fetch and which local refs to update.
	When no <refspec>s appear on the command line, the refs to fetch
	are read from `remote.<repository>.fetch` variables instead
ifndef::git-pull[]
	(see <<CRTB,CONFIGURED REMOTE-TRACKING BRANCHES>> below).
endif::git-pull[]
ifdef::git-pull[]
	(see linkgit:git-fetch[1]).
endif::git-pull[]
+
The format of a <refspec> parameter is an optional plus
`+`, followed by the source ref <src>, followed
by a colon `:`, followed by the destination ref <dst>.
The colon can be omitted when <dst> is empty.
+
`tag <tag>` means the same as `refs/tags/<tag>:refs/tags/<tag>`;
it requests fetching everything up to the given tag.
+
The remote ref that matches <src>
is fetched, and if <dst> is not empty string, the local
ref that matches it is fast-forwarded using <src>.
If the optional plus `+` is used, the local ref
is updated even if it does not result in a fast-forward
update.
+
[NOTE]
When the remote branch you want to fetch is known to
be rewound and rebased regularly, it is expected that
its new tip will not be descendant of its previous tip
(as stored in your remote-tracking branch the last time
you fetched).  You would want
to use the `+` sign to indicate non-fast-forward updates
will be needed for such branches.  There is no way to
determine or declare that a branch will be made available
in a repository with this behavior; the pulling user simply
must know this is the expected usage pattern for a branch.
ifdef::git-pull[]
+
[NOTE]
There is a difference between listing multiple <refspec>
directly on 'git pull' command line and having multiple
`remote.<repository>.fetch` entries in your configuration
for a <repository> and running a
'git pull' command without any explicit <refspec> parameters.
<refspec>s listed explicitly on the command line are always
merged into the current branch after fetching.  In other words,
if you list more than one remote ref, 'git pull' will create
an Octopus merge.  On the other hand, if you do not list any
explicit <refspec> parameter on the command line, 'git pull'
will fetch all the <refspec>s it finds in the
`remote.<repository>.fetch` configuration and merge
only the first <refspec> found into the current branch.
This is because making an
Octopus from remote refs is rarely done, while keeping track
of multiple remote heads in one-go by fetching more than one
is often useful.
endif::git-pull[]