git fetch is a command used to download commits, files, and refs from a remote repository into your local repository. It is used to see what everybody else has been working on and to review commits before integrating them with your local repository. Fetching is similar to svn update in that it lets you see how the central history has progressed, but it doesn’t force you to actually merge the changes into your repository.

When you run git fetch, Git downloads the changes from the remote repository to your local repository, but it does not integrate any of this new data into your working files. Fetched content has to be explicitly checked out using the git checkout command. This makes fetching a safe way to review commits before integrating them with your local repository.

git fetch isolates fetched content from existing local content, and it has absolutely no effect on your local development work. It gives you access to the entire branch structure of another repository. You can use git fetch to see what commits have been added to the upstream main, and then approve the changes and merge them into your local main branch using the git merge command.

In summary, git fetch is a primary command used to download contents from a remote repository. It is used in conjunction with git remote, git branch, git checkout, and git reset to update a local repository to the state of a remote.