Opening 18_1040.xlsx produces maximum number of columns per sheet was exceeded

Platform: Ubuntu Linux 18.04 LTS 64 bit, 8 GB memory, about 20 GB available space in / .

Was reading an article about income taxes and ran across a reference to a spreadsheet version of the IRS tax forms:

    https://sites.google.com/site/excel1040/home/download

Oh, and I had to try loading that from Google into Libre Calc 6.2.2.2 .

That produced the warning:

Warning loading document 18_1040.xlsx:
The data could not be loaded completely because the
maximum number of columns per sheet was exceeded.

Should this warning be ignored?

answered here