`:<dst>` means to update the same ref as the `<src>`.
+
If <dst> doesn't start with `refs/` (e.g. `refs/heads/master`) we will
try to infer where in `refs/*` on the destination <repository> it
belongs based on the type of <src> being pushed and whether <dst>
is ambiguous.
+
--
* If <dst> unambiguously refers to a ref on the <repository> remote,
  then push to that ref.

* If <src> resolves to a ref starting with refs/heads/ or refs/tags/,
  then prepend that to <dst>.

* Other ambiguity resolutions might be added in the future, but for
  now any other cases will error out with an error indicating what we
  tried, and depending on the `advice.pushUnqualifiedRefname`
  configuration (see linkgit:git-config[1]) suggest what refs/
  namespace you may have wanted to push to.

--
+
The object referenced by <src> is used to update the <dst> reference
on the remote side. Whether this is allowed depends on where in
`refs/*` the <dst> reference lives as described in detail below, in
those sections "update" means any modifications except deletes, which
as noted after the next few sections are treated differently.
+
The `refs/heads/*` namespace will only accept commit objects, and
updates only if they can be fast-forwarded.
+
The `refs/tags/*` namespace will accept any kind of object (as
commits, trees and blobs can be tagged), and any updates to them will
be rejected.
+
It's possible to push any type of object to any namespace outside of
`refs/{tags,heads}/*`. In the case of tags and commits, these will be
treated as if they were the commits inside `refs/heads/*` for the
purposes of whether the update is allowed.
+
I.e. a fast-forward of commits and tags outside `refs/{tags,heads}/*`
is allowed, even in cases where what's being fast-forwarded is not a
commit, but a tag object which happens to point to a new commit which
is a fast-forward of the commit the last tag (or commit) it's
replacing. Replacing a tag with an entirely different tag is also
allowed, if it points to the same commit, as well as pushing a peeled
tag, i.e. pushing the commit that existing tag object points to, or a
new tag object which an existing commit points to.
+
Tree and blob objects outside of `refs/{tags,heads}/*` will be treated
the same way as if they were inside `refs/tags/*`, any update of them
will be rejected.
+
All of the rules described above about what's not allowed as an update
can be overridden by adding an the optional leading `+` to a refspec
(or using `--force` command line option). The only exception to this
is that no amount of forcing will make the `refs/heads/*` namespace
accept a non-commit object. Hooks and configuration can also override
or amend these rules, see e.g. `receive.denyNonFastForwards` in
linkgit:git-config[1] and `pre-receive` and `update` in
linkgit:githooks[5].
+
Pushing an empty <src> allows you to delete the <dst> ref from the
remote repository. Deletions are always accepted without a leading `+`
in the refspec (or `--force`), except when forbidden by configuration
or hooks. See `receive.denyDeletes` in linkgit:git-config[1] and
`pre-receive` and `update` in linkgit:githooks[5].
+
The special refspec `:` (or `+:` to allow non-fast-forward updates)
directs Git to push "matching" branches: for every branch that exists on
the local side, the remote side is updated if a branch of the same name
already exists on the remote side.
+
`tag <tag>` means the same as `refs/tags/<tag>:refs/tags/<tag>`.

--all::
--branches::
	Push all branches (i.e. refs under `refs/heads/`); cannot be
	used with other <refspec>.

--prune::
	Remove remote branches that don't have a local counterpart. For example
	a remote branch `tmp` will be removed if a local branch with the same
	name doesn't exist any more. This also respects refspecs, e.g.
	`git push --prune remote refs/heads/*:refs/tmp/*` would
	make sure that remote `refs/tmp/foo` will be removed if `refs/heads/foo`
	doesn't exist.

--mirror::
	Instead of naming each ref to push, specifies that all