diff --git a/hid/main.go b/hid/main.go
index c49b2f6..826ea46 100644
--- a/hid/main.go
+++ b/hid/main.go
@@ -192,27 +192,30 @@ func resolveFilename(filename string, relativeCB func(string) string) string {
 // --- Simple file I/O ---------------------------------------------------------
 
 // Overwrites filename contents with data; creates directories as needed.
-func writeFile(filename string, data []byte) error {
-	if dir := filepath.Dir(filename); dir != "." {
+func writeFile(path string, data []byte) error {
+	if dir := filepath.Dir(path); dir != "." {
 		if err := os.MkdirAll(dir, 0755); err != nil {
 			return err
 		}
 	}
-	return ioutil.WriteFile(filename, data, 0644)
+	return ioutil.WriteFile(path, data, 0644)
 }
 
 // Wrapper for writeFile that makes sure that the new data has been written
 // to disk in its entirety before overriding the old file.
-func writeFileSafe(filename string, data []byte) error {
-	temp := filename + ".new"
+func writeFileSafe(path string, data []byte) error {
+	temp := path + ".new"
 	if err := writeFile(temp, data); err != nil {
 		return err
 	}
-	return os.Rename(temp, filename)
+	return os.Rename(temp, path)
 }
 
 // --- Simple configuration ----------------------------------------------------
 
+// This is the bare minimum to make an application configurable.
+// Keys are stripped of surrounding whitespace, values are not.
+
 type simpleConfigItem struct {
 	key         string // INI key
 	def         string // default value
@@ -229,8 +232,8 @@ func (sc simpleConfig) loadDefaults(table []simpleConfigItem) {
 
 func (sc simpleConfig) updateFromFile() error {
 	basename := projectName + ".conf"
-	filename := resolveFilename(basename, resolveRelativeConfigFilename)
-	if filename == "" {
+	path := resolveFilename(basename, resolveRelativeConfigFilename)
+	if path == "" {
 		return &os.PathError{
 			Op:   "cannot find",
 			Path: basename,
@@ -238,7 +241,7 @@ func (sc simpleConfig) updateFromFile() error {
 		}
 	}
 
-	f, err := os.Open(filename)
+	f, err := os.Open(path)
 	if err != nil {
 		return err
 	}
@@ -253,7 +256,7 @@ func (sc simpleConfig) updateFromFile() error {
 
 		equals := strings.IndexByte(line, '=')
 		if equals <= 0 {
-			return fmt.Errorf("%s:%d: malformed line", filename, lineNo)
+			return fmt.Errorf("%s:%d: malformed line", path, lineNo)
 		}
 
 		sc[strings.TrimRight(line[:equals], " \t")] = line[equals+1:]
@@ -295,13 +298,13 @@ func callSimpleConfigWriteDefault(pathHint string, table []simpleConfigItem) {
 		``,
 	}
 
-	filename, err := simpleConfigWriteDefault(
+	path, err := simpleConfigWriteDefault(
 		pathHint, strings.Join(prologLines, "\n"), table)
 	if err != nil {
 		log.Fatalln(err)
 	}
 
-	log.Printf("configuration written to `%s'\n", filename)
+	log.Printf("configuration written to `%s'\n", path)
 }
 
 // --- Configuration -----------------------------------------------------------