Python and Polybase 2019 supported file format

May I know if SQL Server polybase 2019 (or before) support what kind of data format ?

Json ? xml ? picture ? audio ?

I know that SQL Server 2019 can run python external script , can these python external script access data out of SQL Server (also polybase) , and import it to sql server ?

Any difference between polybase in SQL Server Windows Version and in big data cluster version ?