Ya, I didn't understand this design choice. For a while I've had some custom css which also extends the width of the main content on github as well because I've always found reading some github issues with logs in them challenging.

This is the css I'm running now to fix this, as well as extend the width of the main content. The 1600px is such that when using i3 and having my browser be half the screen it consumes most of the screen space on my 4k monitor.

    :root {
        --width: 1600px;
    }

    .container-xl {
        max-width: var(--width);
    }
    .pagehead {
        padding-left: calc(50% - (var(--width) / 2));
        padding-right: calc(50% - (var(--width) / 2));
    }