When a question becomes a hot network question, the time it became such is shown in the edit history of the question. You can replace the last part of the URL with revisions to see.
I just came across this question, no edits yet so there's no button to click to see edit history.
I tried to "replace" the last part of the URL with revisions in several ways:
https://quant.stackexchange.com/questions/61760/revisions
https://quant.stackexchange.com/questions/61760/why-are-there-no-papers-about-stock-prediction-with-machine-learning-in-leading/revisions
https://quant.stackexchange.com/questions/61760/timeline
https://quant.stackexchange.com/questions/61760/why-are-there-no-papers-about-stock-prediction-with-machine-learning-in-leading/timeline
No luck, all the pages just redirect to or show the original question.
How can I see the time it became hot network question?
/posts/<pistID>/*URL, but withrevisionsinstead oftimeline. So,https://quant.stackexchange.com/posts/61760/revisionsfor the question in which you're interested. Both theposts/timelineand/revisionsURLs work for every question and answer, but the timeline is a bit easier to get to when there's not more than one revision, due to always having the timeline link below the post voting.