Discussion and demonstration of remote tracking branches and adding remotes.

$ git ls-remote [<remote>]
$ git remote -v
$ git remote prune

$ git fetch --all
$ git push origin thisbranch:thatbranch
$ git push origin --delete <branchname>

$ git checkout --track origin/serverfix
$ git checkout -b sf origin/serverfix
$ git branch [-u|--set-upstream-to] origin/serverfix

Shorthand if you're on the master branch:

$ git merge origin/master
$ git merge @{upstream}
$ git merge @{u}

$ git fetch [-p|--prune]

Based on the web page here, first verify that there is only one remote:

$ git remote
origin
$ git remote -v
origin	https://github.com/torvalds/linux.git (fetch)
origin	https://github.com/torvalds/linux.git (push)
$ 

Add the remote with whatever meaningful name works for you:

$ git remote add ln \
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
$

Verify you have a second remote:

$ git remote -v
ln	https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git (fetch)
ln	https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git (push)
origin	https://github.com/torvalds/linux.git (fetch)
origin	https://github.com/torvalds/linux.git (push)
$

Now fetch the new content from the new remote:

$ git fetch [--tags] ln
remote: Counting objects: 109900, done.
remote: Compressing objects: 100% (19971/19971), done.
remote: Total 109900 (delta 95864), reused 103738 (delta 89778)
Receiving objects: 100% (109900/109900), 17.48 MiB | 1.14 MiB/s, done.
Resolving deltas: 100% (95864/95864), completed with 4062 local objects.
From https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next
 * [new branch]                akpm          -> ln/akpm
 * [new branch]                akpm-base     -> ln/akpm-base
 * [new branch]                master        -> ln/master
 * [new branch]                stable        -> ln/stable
 * [new tag]                   next-20171115 -> next-20171115
 * [new tag]                   next-20171116 -> next-20171116
 * [new tag]                   next-20171117 -> next-20171117
 * [new tag]                   next-20171120 -> next-20171120
 * [new tag]                   next-20171121 -> next-20171121
  ... big snip ...
$

List all remote branches in the object store:

$ git branch -r
  ln/akpm
  ln/akpm-base
  ln/master
  ln/stable
  origin/HEAD -> origin/master
  origin/master
$

Start tracking:

$ git checkout -b lnmaster --track ln/master