What LaTeX is
A LaTeX table is a tabular environment: a column specification, ampersands between cells and double backslashes at the end of each row.
Academic papers, theses and anything typeset with LaTeX or written in Overleaf.
What JSON Lines is
JSON Lines is one complete JSON object per line, with no enclosing array and no commas between records. The file is not valid JSON as a whole, and that is the point.
Log pipelines, machine learning datasets and anything that appends records or reads them in a stream.
What changes when you convert LaTeX to JSON Lines
The tabular body is read, rules are dropped, and escaped characters are unescaped. Text wrapped in textbf or emph is reduced to the text itself.
Every row becomes one line. You can append to the file forever without rewriting it, and a reader can process it a line at a time without holding the whole thing in memory.
What carries over from LaTeX to JSON Lines
LaTeX records 3 things about a table that JSON Lines has no way to hold.
JSON Lines wants a type for each column, and LaTeX does not record one, so each column is typed from what its values look like. A column of digits that should stay text - a zip code, a phone number, a leading-zero id - is the usual thing to check afterwards.
A line break inside a cell ends the row in JSON Lines, so line breaks are replaced rather than carried through.
JSON Lines 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 LaTeX - weight, alignment, colour, column widths - has no counterpart in JSON Lines and is dropped. The values are what survives.
The result can be read a record at a time, and appended to by adding to the end of it. That is worth having for a table too large to hold in memory, and it means a JSON Lines file that is cut off part way through still gives you every record before the cut.
This is the direction that recovers structure: LaTeX has no table in it to read, only an arrangement that looks like one, so the rows and columns are inferred rather than read.
The identifier 007 comes out of the JSON Lines 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 JSON Lines file goes wrong.
The quotes around Jonah "Jo" Pryce are escaped with a backslash in the JSON Lines.