Very cool & giving me some inspiration for... stuff.
Momentarily thought they were mailing out hard copies, as they seek a mailing address to check out a book. I get this is likely to comply with copyright obligations, or just because the charity lacks the resources to supply the entire world, but it is a vulnerability should the library be attacked. Suggest users furnish addresses they do not live at - ideally non-residential addresses - addresses of campaign offices of local homophobic & transphobic representatives would work, but so would govt departmental buildings or commercial premises which are used by a lot of people (best to not put some randomer at risk).