The issue filed "Remaining Estimate", which according to this link appears to be standard, has totally disappeared from my Jira Core.
I try to find it in Settings -> Issues -> Field Configurations -> Default screen configuration (which in theory is where I should see all standard fields), it just is not there. As if it never existed. But, I also use BigPicture and from there there's a view which shows me all the standard fields of Jira Core issues, and "Remaining Estimate" is right in the list.
How can I do to make it come back?
Thank you very much in advance
Remaining Estimate isn't a standalone field, it's a part of the field "Time Tracking"
There's a few things to bear in mind with Time Tracking:
To see more about how Time Tracking works, see this page
Time Tracking also looks different on the new view than classic view:
Even though it isn't a standalone field, it should still be possible to utilise as a column in Issue Search, etc.
Let us know if this resolves your queries. If not, please let us know!