Adds counts next to files in pull requests on github.com as a progress indicator for code reviews. Add to your favorite site-specific browser extension (Stylebot is one).

pr-file-counter.css

.files-next-bucket.pull-request-tab-content .file:before {
    background-color: #333;
    border-radius: 50%;
    color: #fff;
    content: counter(file);
    counter-increment: file;
    font-size: 10px;
    font-weight: bold;
    height: 26px;
    line-height: 26px;
    position: absolute;
    right: calc(100% - 13px);
    text-align: center;
    top: 30px ;
    width: 26px;
}

.pr-toolbar-shadow:before {
    content: "";
    height: 60px;
    position: absolute;
    top: -61px;
    width: 100%;
}

body {
    counter-reset: file;
}