What PDF is
PDF describes a page: glyphs at coordinates, not rows and columns. A table in a PDF is a visual arrangement, not a data structure.
Reports, invoices, statements and anything sent to be read rather than processed.
What Trac Wiki is
Trac wiki tables use double pipes around every cell.
Projects still running a Trac instance.
What changes when you convert PDF to Trac Wiki
Every character in a text-based PDF carries its position on the page. Characters sharing a baseline are one row. Columns are found from the vertical strips no character ever occupies, which is why extraction works cleanly on a document laid out with spacing and badly on one laid out with ruled lines. A header repeated at the top of each page is detected and dropped rather than landing in the middle of the data.
Every cell is wrapped in double pipes, which is the whole syntax.
What carries over from PDF to Trac Wiki
PDF records 2 things about a table that Trac wiki has no way to hold.
A line break inside a cell ends the row in Trac wiki, so line breaks are replaced rather than carried through.
Trac wiki marks its header cells differently from its data cells, so the first row is written with that marker.
Anything visual in the PDF - weight, alignment, colour, column widths - has no counterpart in Trac wiki and is dropped. The values are what survives.
This is the direction that recovers structure: PDF has no table in it to read, only an arrangement that looks like one, so the rows and columns are inferred rather than read.