3 files changed, 6 insertions, 6 deletions
diff --git a/plumbing/format/commitgraph/file.go b/plumbing/format/commitgraph/file.go
index 0ce7198..1d25238 100644
--- a/plumbing/format/commitgraph/file.go
+++ b/plumbing/format/commitgraph/file.go
@@ -14,14 +14,14 @@ import (
 var (
 	// ErrUnsupportedVersion is returned by OpenFileIndex when the commit graph
 	// file version is not supported.
-	ErrUnsupportedVersion = errors.New("Unsupported version")
+	ErrUnsupportedVersion = errors.New("unsupported version")
 	// ErrUnsupportedHash is returned by OpenFileIndex when the commit graph
 	// hash function is not supported. Currently only SHA-1 is defined and
 	// supported
-	ErrUnsupportedHash = errors.New("Unsupported hash algorithm")
+	ErrUnsupportedHash = errors.New("unsupported hash algorithm")
 	// ErrMalformedCommitGraphFile is returned by OpenFileIndex when the commit
 	// graph file is corrupted.
-	ErrMalformedCommitGraphFile = errors.New("Malformed commit graph file")
+	ErrMalformedCommitGraphFile = errors.New("malformed commit graph file")
 
 	commitFileSignature    = []byte{'C', 'G', 'P', 'H'}
 	oidFanoutSignature     = []byte{'O', 'I', 'D', 'F'}
diff --git a/plumbing/format/gitattributes/attributes.go b/plumbing/format/gitattributes/attributes.go
index d13c2a9..329e667 100644
--- a/plumbing/format/gitattributes/attributes.go
+++ b/plumbing/format/gitattributes/attributes.go
@@ -15,7 +15,7 @@ const (
 
 var (
 	ErrMacroNotAllowed      = errors.New("macro not allowed")
-	ErrInvalidAttributeName = errors.New("Invalid attribute name")
+	ErrInvalidAttributeName = errors.New("invalid attribute name")
 )
 
 type MatchAttribute struct {
diff --git a/plumbing/format/idxfile/decoder.go b/plumbing/format/idxfile/decoder.go
index 7768bd6..51a3904 100644
--- a/plumbing/format/idxfile/decoder.go
+++ b/plumbing/format/idxfile/decoder.go
@@ -12,9 +12,9 @@ import (
 var (
 	// ErrUnsupportedVersion is returned by Decode when the idx file version
 	// is not supported.
-	ErrUnsupportedVersion = errors.New("Unsupported version")
+	ErrUnsupportedVersion = errors.New("unsupported version")
 	// ErrMalformedIdxFile is returned by Decode when the idx file is corrupted.
-	ErrMalformedIdxFile = errors.New("Malformed IDX file")
+	ErrMalformedIdxFile = errors.New("malformed IDX file")
 )
 
 const (