What Plain Text is
Plain text here means columns lined up with spaces, the way a command line tool prints a table.
Terminal output, log files, fixed-width exports from older systems.
What Firebase is
JSON shaped for a Realtime Database import: an object keyed by record id rather than an array.
Firebase projects.
What changes when you convert Plain Text to Firebase
Two shapes are handled. If the same character positions are blank on every line, those gutters are treated as column boundaries, so values containing single spaces stay intact. Otherwise the lines are split on runs of whitespace.
Keys come from the first column. Firebase does not store arrays natively, so a keyed object is the correct shape for an import.
What carries over from Plain Text to Firebase
One property of the plain text has no home in Firebase, and it is worth knowing which before you convert.
Firebase wants a type for each column, and plain text 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.
Firebase 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.
The identifier 007 comes out of the Firebase 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 Firebase file goes wrong.
The quotes around Jonah "Jo" Pryce are escaped with a backslash in the Firebase.