Appendix A. Identifier prefixes

Ids are a prefix, a hyphen and 12 random lowercase hex digits, except where noted.

Prefix	Entity	Unique within	Section
`doc-`	document	everywhere (libraries refer to it)	4.2
`pg-`	page	the file	4.2
`nd-`	node, including components, component sets and instances	the file	4.3
`st-`	style	the file	4.9
`vc-`	variable collection	the file	4.10
`md-`	mode	the file	4.10
`vr-`	variable	the file	4.10
`lib-`	library reference	the file	4.11
`fl-`	prototype flow	the file	4.12
`cn-`	comment	the file	4.13
`vs-`	named version	the file	4.14
`tx-`	event group	the file	5.7
`ep-`	epoch: the tree written by one consolidation (or at the creation of the file), carried by the `wal.base` marker	everywhere (git history is searched for it)	5.4
`an-`	annotation category added by a user (built-in: `behaviour`, `accessibility`, `interaction`)	the document	4.2
`sha256-`	asset: the prefix and 64 hex digits of the SHA-256 of the file	the assets folder	8.2
`sha256:`	tree hash: the prefix and 64 hex digits of the SHA-256 of the canonical tree; not an id, a name of a state	—	6.9

Composite forms, never generated on their own:

Form	Meaning	Example	Section
`<instance id>/<override path>`	Derived id of an instance sublayer; also the `parent` of slot content	`nd-e7a9c1b3d5f0/nd-2b7d9e4f6a10`	4.8
`<library id>/<id>`	Qualified id of something in a library	`lib-1f3b5d7a9c0e/vr-7b9d1f3a5c7e`	4.11
`<name>#<4 hex>`	Component property key (variant properties: the plain name)	`Label#a41c`	4.8
`nd:<12 hex>`	Input alias of `nd-<12 hex>` accepted by `ud` and the Plugin API, never written	`nd:3f9a0c1e7b2d`	5.5
`ud://<path>.design?node-id=<id>`	Link to a node, accepted by `ud` and the editor	`ud://screens/login.design?node-id=nd-4c6e8a0b2d1f`	CLI-001