I linked to the item's main page, which has other download options for different e-readers, metadata, etc, in addition to the bookreader interface (which provides additional options like Read Aloud and Search Inside (and it's open source! https://github.com/internetarchive/bookreader ).
Apparently the greyed background link at the bottom takes you to the official site but just in the theater view. So I still can't navigate out of it to actually see archive.org without inspecting the url.
I'm mixed on this. archive.org should probably have some branding or site navigable something somewhere, right? nobody has brought it up over at https://github.com/internetarchive/bookreader/ . archive.org is fantastic. I don't know how to suggest to them to surface their brand and the library project.