Where can I get tax XSD files?

Question

Electronic accounting

In the orders of the tax service there are links to XSD files of some documents, for example, for the sales book, it seems like there should be a file called ON_KNPROD_1_899_01_05_01_05.xsd. But I can't find them. I found, apparently, the previous version (..._01.xsd), but it seems to be very old - even "..._04.xsd" is invalid since 2013. In addition to it, only orders with file names were found, and the files themselves are nowhere to be seen.
Question: where to get them?