What HTML is
An HTML table is a table element containing thead and tbody, with th cells for headers and td cells for data.
Web pages, email templates and anything pasted into a CMS.
What XML is
XML marks up data with nested named tags and optional attributes. It is verbose, strict about being well-formed, and can carry a schema that says what shape a document must have.
Enterprise integrations, government data feeds, RSS, SOAP services and older document formats.
What changes when you convert HTML to XML
The first table in the markup is used. Cell contents are stripped of inline tags and entities are decoded, so <td><b>Total</b> </td> arrives as Total. Nested tables inside a cell are not descended into.
Each row becomes an element with one child per column. Header names are rewritten where they have to be, because an XML tag cannot start with a digit or contain a space, so a column called 2024 Sales becomes _2024_Sales.
What carries over from HTML to XML
HTML records 2 things about a table that XML has no way to hold.
XML has no header row. The column names are repeated as keys on every record instead, which is why the result is bigger on disk than the table it came from.
Anything visual in the HTML - weight, alignment, colour, column widths - has no counterpart in XML and is dropped. The values are what survives.
The identifier 007 comes out of the XML as 007. Reading it as a number would have made it 7, and an id that changes value is worse than one that stays text.
The role "Analyst, data" survives with its comma, in one cell rather than split across two. That is the first thing to check in any converted table, and the usual place a XML file goes wrong.
The quotes around Jonah "Jo" Pryce are written as the HTML entity " in the XML.