How to merge on your machine?
git fetch origin refs/mr/@@if("@@mr::id@@" == ""){{ID}}{{@@mr::id@@}}:mr-@@if("@@mr::id@@" == ""){{ID}}{{@@mr::id@@}}
git checkout master
git merge mr-@@if("@@mr::id@@" == ""){{ID}}{{@@mr::id@@}}

To "see" all the merge requests as branches,
add, in the config file (.git/config), under the remote you want, a line like this:
fetch = +refs/mr/*:refs/remotes/your_remote_name_for_example_origin/mr/*
After you run a git fetch, you will have all the pull requests locally.
For example, you can merge one of them:
git checkout master
git merge mr/@@if("@@mr::id@@" == ""){{ID}}{{@@mr::id@@}}