How to get reference to selected assets in content browser?

This gives you all the selected assets:

    TArray<FAssetData> AssetDatas;
    FContentBrowserModule& ContentBrowserModule = FModuleManager::LoadModuleChecked<FContentBrowserModule>("ContentBrowser");
    IContentBrowserSingleton& ContentBrowserSingleton = ContentBrowserModule.Get();
    ContentBrowserSingleton.GetSelectedAssets(AssetDatas);

The problem with GEditor->GetSelectedObjects() is that it doesn’t include assets that haven’t been loaded yet, even if they are selected in the GUI.