Insert Header area empty

A while back I inserted Google Analytics code in the header area using this plug-in. Everything worked and the code is still there. Later I added an anchor link to the header section (for a Back to Top link). It works as well. However, I now need to update the Google code and the only thing showing in the Scripts in Header section of the plugin is the anchor link. No Google Code, which means I can’t update it. I could add everything again, including the new line of code I need to add, but I’m pretty sure all that will do is add the Google code a second time. I need access to the original code I added. What’s going on with this plugin?

https://ww.wp.xz.cn/plugins/insert-headers-and-footers/