Discuss generator magic number reservations.
diff --git a/README.md b/README.md
index 2ea3dc5..b1aa964 100644
--- a/README.md
+++ b/README.md
@@ -23,15 +23,28 @@
the SPIR-V Working Group will push new commits onto master, updating
the files under [include](include).
-The SPIR-V XML registry file is updated by Khronos whenever a new enum range is allocated.
+[The SPIR-V XML registry file](include/spirv/spir-v.xml)
+is updated by Khronos whenever a new enum range is allocated.
Pull requests can be made to
- request allocation of new enum ranges in the XML registry file
+- register a new magic number for a SPIR-V generator
- reserve specific tokens in the JSON grammar
+### Registering a SPIR-V Generator Magic Number
+
+Tools that generate SPIR-V should use a magic number in the SPIR-V to help identify the
+generator.
+
+Care should be taken to follow existing precedent in populating the details of reserved tokens.
+This includes:
+- keeping generator numbers in numeric order
+- filling out all the existing fields
+
### Reserving tokens in the JSON grammar
-Care should be taken to follow existing precedent in populating the details of reserved tokens. This includes:
+Care should be taken to follow existing precedent in populating the details of reserved tokens.
+This includes:
- pointing to what extension has more information, when possible
- keeping enumerants in numeric order
- when there are aliases, listing the preferred spelling first
