Hi, We have been trying to use it on frwikisource, for books that are now PD is US also :D
for configuration, I began by copying the enws file https://www.mediawiki.org/wiki/Extension:FileImporter/Data/fr.wikisource - but the configuration is quite tricky, and not easy to do...
we would like to automatically add the Book template, to add info... but, I do not understand how to do this :(