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 PHP Array is
A PHP array literal: an outer array of rows, each an associative array keyed by column name.
PHP applications that need a lookup table in code rather than in a database.
What changes when you convert JSON Lines to PHP Array
Each line is parsed on its own, so a corrupt record does not take the file with it. Keys are unioned across lines in first-seen order, so a record missing a field leaves that cell empty rather than shifting the columns.
Values are single-quoted with backslashes and quotes escaped, so the output can be pasted into a file as is.
What carries over from JSON Lines to PHP Array
One property of the JSON Lines has no home in PHP, and it is worth knowing which before you convert.
JSON Lines can be read one record at a time. PHP has to be complete before it means anything, so the whole table is held in memory while it is written and a file that gets cut off part way through is not partly usable - it is unusable.
Both formats record types, so numbers, booleans and nulls survive as themselves rather than as text.
The identifier 007 comes out of the PHP Array 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 PHP Array file goes wrong.
The quotes around Jonah "Jo" Pryce are left as a plain quote character in the PHP Array.