rename tbs_certificate to tbs_certificate_bytes, add a comment
diff --git a/src/cryptography/hazmat/backends/openssl/x509.py b/src/cryptography/hazmat/backends/openssl/x509.py
index 0e5ab91..3afbc40 100644
--- a/src/cryptography/hazmat/backends/openssl/x509.py
+++ b/src/cryptography/hazmat/backends/openssl/x509.py
@@ -327,8 +327,9 @@
         return self._backend._asn1_string_to_bytes(self._x509.signature)
 
     @property
-    def tbs_certificate(self):
+    def tbs_certificate_bytes(self):
         pp = self._backend._ffi.new("unsigned char **")
+        # the X509_CINF struct holds the tbsCertificate data
         res = self._backend._lib.i2d_X509_CINF(self._x509.cert_info, pp)
         self._backend.openssl_assert(res > 0)
         pp = self._backend._ffi.gc(
diff --git a/src/cryptography/x509/base.py b/src/cryptography/x509/base.py
index 53893a1..ad561b9 100644
--- a/src/cryptography/x509/base.py
+++ b/src/cryptography/x509/base.py
@@ -124,7 +124,7 @@
         """
 
     @abc.abstractproperty
-    def tbs_certificate(self):
+    def tbs_certificate_bytes(self):
         """
         Returns the tbsCertificate payload bytes as defined in RFC 5280.
         """