In excel, how display text in a cell while hiding a formula referencing another cell and tab?

I have a spreadsheet, tab 1, whereby cell A1 displays as "account name". if i am positioned in cell A1, and i look at the fx bar, i do not see "account name", like one would think. instead, i see the following formula =detail!a1 this cell is referring to cell A1 in the adjacent tab, tab 2, of the workbook. how did the person who programmmed this do it please?. i need to know because i will need to do this sort of thing from now on, but the person who did it isn't available. thanks!