diff --git a/docs/source/markdown/podman-build.1.md.in b/docs/source/markdown/podman-build.1.md.in
index 102c0d02b1..202cd228e1 100644
--- a/docs/source/markdown/podman-build.1.md.in
+++ b/docs/source/markdown/podman-build.1.md.in
@@ -13,7 +13,9 @@ podman\-build - Build a container image using a Containerfile
 Containerfiles or Dockerfiles and a specified build context directory. A
 Containerfile uses the same syntax as a Dockerfile internally. For this
 document, a file referred to as a Containerfile can be a file named
-either 'Containerfile' or 'Dockerfile'.
+either 'Containerfile' or 'Dockerfile' exclusively. Any file that has additional
+extension attached will not be recognized by `podman build .` unless a `-f` flag is
+used to specify the file.
 
 The build context directory can be specified as the http(s) URL of an archive,
 git repository or Containerfile.