and here is the dba_data_files query
FILE_ID TABLESPACE_NAME BYTES BLOCKS STATUS RELAT
IVE_F AUT MAXBYTES MAXBLOCKS INCREMENT_ USER_BYTES USER_BLOCK
6 INDX 339437568 165741 AVAILABLE
6 YES 8589930496 4194302 1 339435520 165740

which shows that autoextend is yes