In this case, it's the creation date of the place, so I'd ask the person who created it. Please note that the date I set is in the past, which helps local mappers identify outdated elements and re-verify them. There is a near 100% probability that this place no longer exists, so someone needs to check it and either bump check_date to the current day or make amends/delete the record, check_date makes it easier to draw attention to that fact.

I hear many complaints about unreliable/outdated data, most of those complaints are related to places which were added ~10 years ago, so it's pretty important to be able to highlight the unreliable places so users can avoid them and local editors can easily identify the low hanging fruits.

Here is an example of a similar effort, it's a pretty common issue:

https://botsin.space/@restobot