diff --git a/build/git.go b/build/git.go
index e7b5d8eb..d80a00ba 100644
--- a/build/git.go
+++ b/build/git.go
@@ -67,7 +67,13 @@ func getGitAttributes(ctx context.Context, contextPath string, dockerfilePath st
 	if sha, err := gitc.FullCommit(); err != nil && !gitutil.IsUnknownRevision(err) {
 		return res, errors.Wrapf(err, "buildx: failed to get git commit")
 	} else if sha != "" {
-		if gitc.IsDirty() {
+		checkDirty := false
+		if v, ok := os.LookupEnv("BUILDX_GIT_CHECK_DIRTY"); ok {
+			if v, err := strconv.ParseBool(v); err == nil {
+				checkDirty = v
+			}
+		}
+		if checkDirty && gitc.IsDirty() {
 			sha += "-dirty"
 		}
 		if setGitLabels {
diff --git a/build/git_test.go b/build/git_test.go
index 18d995b0..5d65b64b 100644
--- a/build/git_test.go
+++ b/build/git_test.go
@@ -131,6 +131,7 @@ func TestGetGitAttributes(t *testing.T) {
 
 func TestGetGitAttributesDirty(t *testing.T) {
 	setupTest(t)
+	t.Setenv("BUILDX_GIT_CHECK_DIRTY", "true")
 
 	// make a change to test dirty flag
 	df := []byte("FROM alpine:edge\n")
diff --git a/docs/reference/buildx_build.md b/docs/reference/buildx_build.md
index 60ea921a..5f77c92f 100644
--- a/docs/reference/buildx_build.md
+++ b/docs/reference/buildx_build.md
@@ -414,8 +414,13 @@ The `registry` exporter is a shortcut for `type=image,push=true`.
 
 Set the target platform for the build. All `FROM` commands inside the Dockerfile
 without their own `--platform` flag will pull base images for this platform and
-this value will also be the platform of the resulting image. The default value
-will be the current platform of the buildkit daemon.
+this value will also be the platform of the resulting image.
+
+The default value is the platform of the BuildKit daemon where the build runs.
+The value takes the form of `os/arch` or `os/arch/variant`. For example,
+`linux/amd64` or `linux/arm/v7`. Additionally, the `--platform` flag also supports
+a special `local` value, which tells BuildKit to use the platform of the BuildKit
+client that invokes the build.
 
 When using `docker-container` driver with `buildx`, this flag can accept multiple
 values as an input separated by a comma. With multiple values the result will be