Column whose fields are formatted to automatically display a number from each row of the table.
This number will be assigned to each row of the table.
This number has always started with 1 for the first table title, 2 for the second title, and so on, as many times as there will be a line:
Column fields of this type are not editable, allowing, among others, to be able to use those as a unique identifier.
What you should know
Automatic numbers will be assigned to all existing lines in the table.
If, for example, you are on a filtered view, an automatic number will also be assigned to each field of any row that does not appear in the filter: