Google bot requests on unknown pages from my website

I see some 404 errors in my search console panel. it's pages like "/m4eu5ebanday.thermosonde" or "/hgcrdie29intt.navidrex". Such pages never existed on website or sitemap.xml. Also I see notice about them "URL might be known from other sources that are currently not reported".
Accourding webserver's logs, that it's really was Google bot.

• Where could Googbot get these links?
• Is this preparation for a website hack or something like that?