The website virtualagc.gibhub.io/virtualagc is a kind of "staging area" existing entirely within GitHub for the real Virtual AGC website at www.ibiblio.org/apollo, but has no normal uses outside of occasional debugging. It may not be fully functional, in the sense that documents and other objects at relative (vs absolute) hyperlinks may not work, since those objects will be at ibiblio.org rather than here on GitHub. (Some links will work because of embedded javascript that attempts to correct them, but not all links have been doctored in this way.)
Because the staging area is not fully functional as a mirror for the real website, we don't want it to show up in search engines. Therefore, the top-level folder (virtualagc.github.io) should have a robots.txt file disallowing all search-engine access.
The file google...html is a verification file demonstrating ownership (RSB) to Google for reindexing requests.
Although this top-level folder has an index.html file, the content of that file should not mimic anything that would mislead anybody to think that it's real Virtual AGC. I don't know if the index file is actually necessary, but we put it in there originally and I don't feel like second-guessing that decision now.