META, XML and identifier hashes

META resources describe their own structures, enums and data blocks. A structure description gives its hashed name, byte size and fields; each field gives a hashed name, offset, kind and referenced type. Maps (ymap) and archetype dictionaries (ytyp) use this representation. Proven

The structural census covers every YMAP and YTYP copy in every archive: 19,941 maps and 2,869 archetype files. Every root, array and pointer decodes through the stored descriptions with no refused files or unreached data-block bytes. The proven header, field and kind descriptions below have that scope; the separate RBF examples do not. Proven · all YMAP and YTYP entries

META’s block references pack a 1-based block ID in the low 12 bits and a byte offset in the next 20 bits. An array of structures can continue at the beginning of the next block when it outgrows one block. Proven

Hash domains

Schema identifiers are case-sensitive Jenkins hashes: CMapData hashes to 0xD3593FA6. Asset names normally use lowercase joaat instead. Applying case folding to a schema identifier changes the lookup. Proven

The Jenkins one-at-a-time mix starts with h = 0. For each byte: add the byte, add h << 10, then XOR h >> 6. After the final byte: add h << 3, XOR h >> 11, then add h << 15; additions wrap at 32 bits. Sourced · CodeWalker

The NG cipher has a separate lookup-table-based name hash; it does not share the plain filename-hash procedure. Sourced · CodeWalker

Container descriptions

The following offsets are in the decoded resource’s system root, not in the compressed file. Proven

META root header112 bytes43% known

ProvenObservedSourcedInferredUnknownNot described

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

0x0

resource basebytes

0x10

identifieru32 = 0x50524430

header versionu16 = 0x79

encrypted strings flagu8

unknown bytesbytes

root block IDu32

0x20

structure descriptionspointer

enum descriptionspointer

0x30

data block tablepointer

name stringpointer

0x40

encrypted stringspointer

structure countu16

enum countu16

block countu16

unknown tailbytes

0x50

… unknown tail

0x60

… unknown tail

Offset	Size	Type	Field	Confidence	Notes
0x0	16	bytes	resource base	Sourced
0x10	4	u32 = 0x50524430	identifier	Proven
0x14	2	u16 = 0x79	header version	Proven
0x16	1	u8	encrypted strings flag	Sourced	0 or 1; CodeWalker's HasEncryptedStrings
0x17	5	bytes	unknown bytes	Unknown	zero in accepted resources
0x1C	4	u32	root block ID	Proven
0x20	8	pointer	structure descriptions	Proven
0x28	8	pointer	enum descriptions	Proven
0x30	8	pointer	data block table	Proven
0x38	8	pointer	name string	Proven
0x40	8	pointer	encrypted strings	Sourced	CodeWalker's pointer to the encrypted strings
0x48	2	u16	structure count	Proven
0x4A	2	u16	enum count	Proven
0x4C	2	u16	block count	Proven
0x4E	34	bytes	unknown tail	Unknown	zero in accepted resources

A structure description’s word at offset 8 is an alignment code, n << 8 with n from 0 to 4 (0, 256, 512, 768, 1024), n being the base-2 logarithm of the alignment. In ragekit’s count over Legacy files it equals the alignment of the widest field in 38,377 of 39,225 descriptions. Sourced · ragekit

META field description16 bytes94% known

ProvenObservedSourcedInferredUnknownNot described

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

0x0

field name hashu32

byte offsetu32

kindu8

unknownu8

reference indexi16

reference keyu32

Offset	Size	Type	Field	Confidence	Notes
0x0	4	u32	field name hash	Proven
0x4	4	u32	byte offset	Proven
0x8	1	u8	kind	Proven
0x9	1	u8	unknown	Unknown
0xA	2	i16	reference index	Proven
0xC	4	u32	reference key	Proven

Kind code	Representation	Confidence
0x01	Boolean	Proven
0x10–0x15	Signed/unsigned 8-, 16- and 32-bit integers, in pairs	Proven
0x21, 0x33, 0x34	Float, vec3, vec4	Proven
0x4A	Hash	Proven
0x05, 0x07	Inline structure, structure pointer	Proven
0x52	Array	Proven
0x40, 0x44, 0x50, 0x59	Fixed characters, character pointer, inline data, data block	Proven
0x60, 0x62–0x65	Enum/flag variants	Proven

XML and RBF

Mount and water configuration includes text XML. Other configuration, including gtxd.ymt, uses RBF, a binary element tree beginning with RBF0. The extension .ymt alone therefore does not identify META. Observed

RBF records use a descriptor-index byte and type byte. A previously unseen descriptor introduces a 16-bit name length and name. Element-open records carry three 16-bit words, the third counting attributes. Observed

RBF type/marker	Value	Confidence
0x00	Open element	Observed
0x10	u32	Observed
0x20, 0x30	True, false	Observed
0x40, 0x50	Float, three floats	Observed
0x60	String with 16-bit length	Observed
FF FF	Close element	Observed
FD FF	Text, with 32-bit byte length	Observed

What do the unnamed META header and field bytes control?

Their locations are known, but zero values or a limited value range do not establish their meaning. Unknown