Future file associations for spreadsheets

I have started a project involving my patrilineage, written on a Libre Office spreadsheet for eventual archiving.
I realise that in the far distant future file associations for spreadsheets might well move on. I want to choose one that can be easily opened on most spreadsheet apps and also projects itself forward in time as one that will probably still be useable in a hundred years time, so the data can be subsequently updated. I realise it is a big ask and probably stretching an expert opinion to that of an educated guess. However your guess will probably be a much better one than my own.
The file will be a simple listing of data with no requirement for equations etc.
I have failed to append the drop down “save file type” but I’m sure you know it. My apology for not finding the paperclip


For 100 years I would suggest a printed copy in Liberation Sans 11 to 12 point on archive paper as backup. 30 years ago you might have chosen .123 or .csv but finding something to read the 5 1/4 inch floppy disc is going to be tricky, especially if the disc has deteriorated.

And use a printer with pigment based water proof ink so it won’t fade or run.