Why the double check for Shell/JavaScript versions in extensionSystem.js?  The second check does not appear to be doing anything new except setting meta.state.  Surely this code could be improved to remove the second check.

    if (!versionCheck(meta['shell-version'], Config.PACKAGE_VERSION) ||
        (meta['js-version'] && !versionCheck(meta['js-version'], Config.GJS_VERSION))) {
        logExtensionError(uuid, 'extension is not compatible with current GNOME Shell and/or GJS version');
        return;
    }

    extensionMeta[uuid] = meta;
    meta.type = type;
    meta.dir = dir;
    meta.path = dir.get_path();
    meta.error = '';

    // Default to error, we set success as the last step
    meta.state = ExtensionState.ERROR;

    if (!versionCheck(meta['shell-version'], Config.PACKAGE_VERSION) ||
        (meta['js-version'] && !versionCheck(meta['js-version'], Config.GJS_VERSION))) {
        logExtensionError(uuid, 'extension is not compatible with current GNOME Shell and/or GJS version', ExtensionState.OUT_OF_DATE);
        meta.state = ExtensionState.OUT_OF_DATE;
        return;
    }