Last known modification date

What exactly is meant by “Last known modification date” at the search results?

I don’t think that the last known modification date of an explicit webpage is meant.

Does that describe the e.g. a newer search of the same webpage is meant or is a newer search of a second yacy server of the same webpage is meant?

Thats the “moddate” of the document which is set by the http response header “Last-Modified”. This date is “wrong” is several ways:

  • as a search user, you just get that that from the last crawl time where it is unknown to the searcher when that was. But this is common for all search engines.
  • the web servers which delivers the web pages during crawl time mostly set that time to current time because a long history of search engine optimization madness caused that this was the best way to go since search portals preferred more recent search results. The date given by the server are therefore mostly not the time when the document was edited by the author of the web page.