What Excel is
An Excel workbook is a zip archive of XML parts describing sheets, cells, formulas, styles and charts. The .xlsx extension is that format; .xls is the older binary one from before 2007.
Finance, operations and anyone who received a file from finance or operations.
What AsciiDoc is
AsciiDoc tables are delimited by |=== and take a cols attribute describing the columns.
Antora documentation sites, and technical writing teams that outgrew Markdown.
What changes when you convert Excel to AsciiDoc
Only the first sheet is read, and cells are read as the text Excel displays rather than the number underneath. That matters for dates: a cell showing 15/03/2026 arrives as that string, not as a serial number you would then have to decode.
The header option is set so the first row renders as a header row rather than data.
What carries over from Excel to AsciiDoc
Excel records 2 things about a table that AsciiDoc has no way to hold.
Excel distinguishes a number from the text of a number; AsciiDoc does not, so every value arrives as text and has to be re-parsed by whatever reads it next.
An empty cell and a missing one are the same thing in AsciiDoc, so a null and an empty string in the Excel both come out blank and can no longer be told apart.
AsciiDoc marks its header cells differently from its data cells, so the first row is written with that marker.