I use Coingecko's importJSON code to load data into a Google Sheet. The last parameter of the url (see below) is called 'doNotDelete!$A$!'. If I run the importJSON function in my sheet a numeric value in cell A1 of the tab doNotDelete shows up. What does this number mean? Is it the number of seconds that past since last execution? There is no explanation about it in the Coingecko's article about their API ImportJSON function for Google Sheets.
=ImportJSON("https://api.coingecko.com/api/v3/coins/markets?vs_currency=usd&order=market_cap_desc&per_page=250&page=2&sparkline=false","/name,/current_price,/market_cap,/price_change,/total_volume,/high_24h,/low_24h","noTruncate,noHeaders",doNotDelete!$A$1)