Card: describe the cleanup

README.md

@@ -13,8 +13,12 @@ every book: title, author, language, source page, EPUB file, cover and size.
 Every work is in the public domain both in the United States (published before
 1930) and in countries with a life + 70 years term; translations are old ones.
 
-- **Standard Ebooks** (English): released under CC0 by Standard Ebooks.
+- **Standard Ebooks** (English): released under CC0 by Standard Ebooks; the
+  imprint, colophon, uncopyright and half-title pages are left out of the
+  reading order.
 - **Project Gutenberg** (other languages): public domain; each file keeps the
   Project Gutenberg License it was distributed with.
-- **Russian Wikisource** via ws-export: public-domain texts; the export's
-  "about" page with its attribution is kept, embedded fonts are removed.
+- **Russian Wikisource** via ws-export: public-domain texts; wiki navigation,
+  the work's index page, the export title page, footnote markers and later
+  editions' notes are removed, as are embedded fonts; the export's "about"
+  page with its attribution is kept.