Hasn't been documented anywhere yet I think:
FRLG/E e-Berry Structure
FRLG: Section 4 - 0x026C
E: Section 4 - 0x0378
0x00 - 0x06 berry name + 0xFF string terminator
0x07 firmness
0x08 - 0x09 size (in mm)
0x0A max yield
0x0B min yield
0x0C - 0x0F berry tag line 1 ROM offset
0x10 - 0x13 berry tag line 2 ROM offset
0x14 growth time per stage (in hours)
0x15 - 0x19 flavor
0x1A smoothness
0x1B 0
0x1C - 0x1F effect in bag
0x24 - 0x27 unknown pointer
0x28 - 0x2B unknown pointer
0x2D - 0x2E unknown
0x2E - 0x2F effect as held item
0x30 - 0x33 checksum
The size is 52 bytes.
Checksum is calculated the same way as in RS, except that it does not skip 0xC - 0x14 for the sum.