Yes there is html there.
The html created by admin/index.php has “body” of class “invisible”, which has style visibility:hidden.
Removing that class results in some display (left hand column and login button). However nothing much else appears and I suspect here are other parts of the page which also have the “hidden” style.
I noticed that phpList3ToBootstrap.js calls a function “removeClass” to remove the invisible class from “body” and the comment says that this happens “after loading”. I suspect that after the page loads, subject to security checks etc. the relevant parts of the page are supposed to display. Bearing in mind that my current page is a completely fresh installation the part which should display is that described in the manual, which would enable me to create the correct tables in the database.
However, it looks like something is preventing this happening. Perhaps phpList3ToBootstrap.js is not being loaded for some reason or there is a switch which is preventing the usual “unhiding” procedures from being implemented.
This will be too complicated for me to try to fix and I haven’t got the time to do this anyway - also any repair would be rubbed out on the first update.
I do not think I have any unusual arrangement. My site is hosted by Crazy Domains in Australia and I am using Google Chome, although MS Edge gives the same results - and as I said it worked perfectly before. It is very strange however that no one else has reported this issue.