diff --git a/peps/pep-0825.rst b/peps/pep-0825.rst
index 3b3e7d0a2d5..5733c215dac 100644
--- a/peps/pep-0825.rst
+++ b/peps/pep-0825.rst
@@ -70,6 +70,26 @@ The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 document are to be interpreted as described in :rfc:`2119`.
 
 
+Implementation requirements
+---------------------------
+
+This specification is written from the perspective of file format producers.
+In the context of format definitions, the word "MUST" specifically
+indicates that the requirement must be satisfied for the data to be
+considered valid according to this specifications.
+
+Tools that produce the data formats according to this specification
+(variant wheels, the index-level metadata file) MUST always produce
+files that meet the requirements of this specification.
+
+Tools that consume the data formats according to this specification
+SHOULD refuse to process the files that do not meet these requirements.
+In this case, it is recommended to follow the same behavior as for
+invalid Core Metadata in wheel files. For example, a wheel index may
+reject the upload, while a package manager may skip the version
+entirely.
+
+
 Variant wheel
 -------------