page header structure in 9.40

Hi, what is the exact structure of the page header in 9.40 ? Versions < 9.40: we have 24 byte for the header including 4 byte page address (3 nibbles(12 bit) chunk#, 5 nibbles(20 bit) page_offset ) pg_addr 4 Byte pg_stamp 4 pg_nslots 2 pg_flags 2 pg_frptr 2 pg_frcnt 2 pg_next 4 pg_prev 4 Version 9.40: I created a chunk larger 2 Gbyte (more than 2**20 = 1.048.576 pages possible ) oncheck -pP shows 24 Byte page header ( slot 1 starts at 24 )where and how are chunk# and pageoffset stored or what is missed in comparison to the old (9.30) format ??? TIA Ruediger Papke