So GitHub's "Repository Refresh" layout is live now and they haven't fixed the damn .repohead (with the repo name and the links to Issues, Pull Requests, etc.) stretchting across the entire screen instead of being constrained to the middle column :/

If it annoys you just as much as it does me, just wack this CSS into a user css extensions and it's fixed:

.repohead .d-flex:first-of-type {
max-width: 1280px !important;
margin-left: auto !important;
margin-right: auto !important;
}
.repohead nav.js-repo-nav {
max-width: 1280px !important;
margin-left: auto !important;
margin-right: auto !important;
}
.repohead .UnderlineNav {
/* Remove repohead bottom divider */
box-shadow: none;
background-color: transparent !important;
}
.repohead {
/* Add repohead bottom divider to repohead so it stretches across the entire screen */
box-shadow: inset 0 -1px 0 #e1e4e8;
}