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 MediaWiki is
MediaWiki table markup opens with {| and a class, marks headers with an exclamation mark and rows with |-.
Wikipedia editors and anyone running a MediaWiki install.
What changes when you convert HTML to MediaWiki
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.
The wikitable class is applied, which is what gives the table borders and header shading on Wikipedia.
What carries over from HTML to MediaWiki
One property of the HTML has no home in MediaWiki, and it is worth knowing which before you convert.
Anything visual in the HTML - weight, alignment, colour, column widths - has no counterpart in MediaWiki and is dropped. The values are what survives.
The identifier 007 comes out of the MediaWiki 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 MediaWiki file goes wrong.
The quotes around Jonah "Jo" Pryce are left as a plain quote character in the MediaWiki.