As the title says, where are stored these logs?

In my case, calibre editor crashed (seems to be more often), I suspect it may be a lack of memory (not "bulk" RAM, for there are still 8GB or so, but rather that used for graphics, sprites, fonts, icons, I do not remember right now its name).
I forgot to mention, it happened on several versions of calibre, this is why I suspect it has something to do with the OS.
Specifically, there are versions 4.2 and 2.50. Never had an issue in many years I used 2.50 on w10 pro, until very recently.
OS is w10 pro 64b.
There are no crash logs on windows. Generally a crash will be because of incompatibilities with the GPU driver. Try updating it, or turn off hardware rendering in webengine https://doc.qt.io/qt-5/qtwebengine-debugging.html