diff --git a/docs/src/guide/index.md b/docs/src/guide/index.md
index 7b35dd66cc..239235a279 100644
--- a/docs/src/guide/index.md
+++ b/docs/src/guide/index.md
@@ -676,6 +676,28 @@ If the provided capability has no invoke method, the return value here functions
 as `getCapability` including returning `undefined` if the capability is not 
 exposed.
 
+### Identifier Syntax
+
+For most purposes, a domain object identifier can be treated as a purely
+symbolic string; these are typically generated by Open MCT Web and plug-ins
+should rarely be concerned with its internal structure.
+
+A domain object identifier has one or two parts, separated by a colon.
+
+* If two parts are present, the part before the colon refers to the space
+  in which the domain object resides. This may be a persistence space or
+  a purely symbolic space recognized by a specific model provider.
+* If only one part is present, the domain object has no space specified,
+  and may presume to reside in the application-configured default space
+  defined by the `PERSISTENCE_SPACE` constant.
+
+```bnf
+<identifier> ::= <space> ":" <simple id> | <simple id>
+<space> ::= <id char>+
+<simple id> ::= <id char>+
+<allowed char> ::= <letter> | <digit> | "-" | "." | "_"
+```
+
 ## Domain Object Actions
 
 An `Action` is behavior that can be performed upon/using a `DomainObject`. An 
@@ -2323,6 +2345,12 @@ default paths to reach external services are all correct.
 
 ### Configuration Constants
 
+The following constants have global significance:
+* `PERSISTENCE_SPACE`: The space in which domain objects should be persisted
+  (or read from) when not otherwise specified. Typically this will not need
+  to be overridden by other bundles, but persistence adapters may wish to
+  consume this constant in order to provide persistence for that space.
+
 The following configuration constants are recognized by Open MCT Web bundles:
 * CouchDB adapter - `platform/persistence/couch`
     * `COUCHDB_PATH`: URL or path to the CouchDB database to be used for domain