diff --git a/tests/qemucapabilitiesdata/README.rst b/tests/qemucapabilitiesdata/README.rst
index 90e240f800..727695c6b0 100644
--- a/tests/qemucapabilitiesdata/README.rst
+++ b/tests/qemucapabilitiesdata/README.rst
@@ -116,3 +116,21 @@ The tool validates and updates the numbering of the entries in the QMP dump in
 case something was modified.
 
 The tool also allows programatic modification of the ``.replies`` file.
+
+Fake test data dumps for certain architectures
+==============================================
+
+For some architectures it was impossible or impractical to fetch real capability
+dumps. To ensure coverate of certain cases the dumps were collected from
+corresponding binaries running on a different architecture.
+
+Capabilities dumps for the following architectures are usually produced on real
+hardware:
+
+  - x86_64
+  - aarch64
+  - ppc64
+  - s390x
+
+In most other cases, x86_64 will be used as the host architecture. A fake caps
+dump can be usually spotted by absence of KVM support.