The University of Adelaide, Australia, offers many hundreds of well-edited, public domain ebooks at
https://ebooks.adelaide.edu.au. I have found at least two old requests on this forum for the catalogue of this collection (
https://ebooks.adelaide.edu.au/opds/root.xml) to be added to GetBooks, as well as one recent post on GitHub reporting its absence from GetBooks as a "bug" in Calibre. Can anyone undertake writing a plugin (in Python, I believe), which I am not capable of doing? (Six years ago, Kovid Goyal posted here that, to write a new GetBooks plugin, look at the calibre source code for example plugins for various stores.)
Thanks!