item_data base for all layer items (different types have different extensions):
[1] _version (not used, was uninitialized)
[1] type
[1] flags
With the extension being
item_data extension for tilemap layers:
[1] version
[1] width
[1] height
[1] flags
[4] color: Color
[1] opt *color_envelope
[1] color_envelope_offset
[1] opt *image
[1] &data: 2d-array of the the tile type 'Tile'
version 3 extension:
[3] name: I32String
DDNet extension (no version change):
[1] opt &data_tele
[1] opt &data_speedup
[1] opt &data_front
[1] opt &data_switch
[1] opt &data_tune
Which confuses me. The base doesn't have any data or a data index reference