diff --git a/internal/filtering/rulelist/engine.go b/internal/filtering/rulelist/engine.go
index b11c71f5..27d45843 100644
--- a/internal/filtering/rulelist/engine.go
+++ b/internal/filtering/rulelist/engine.go
@@ -19,6 +19,7 @@ import (
 //
 // TODO(a.garipov): Merge with [TextEngine] in some way?
 type Engine struct {
+	// logger is used to log the operation of the engine and its refreshes.
 	logger *slog.Logger
 
 	// mu protects engine and storage.
@@ -32,8 +33,7 @@ type Engine struct {
 	// storage is the filtering-rule storage.  It is saved here to close it.
 	storage *filterlist.RuleStorage
 
-	// name is the human-readable name of the engine, like "allowed", "blocked",
-	// or "custom", used to report errors.
+	// name is the human-readable name of the engine.
 	name string
 
 	// filters is the data about rule filters in this engine.
@@ -46,8 +46,8 @@ type EngineConfig struct {
 	// Logger is used to log the operation of the engine.  It must not be nil.
 	Logger *slog.Logger
 
-	// name is the human-readable name of the engine, like "allowed", "blocked",
-	// or "custom", used to report errors.
+	// name is the human-readable name of the engine; see [EngineNameAllow] and
+	// similar constants.
 	Name string
 
 	// Filters is the data about rule lists in this engine.  There must be no
@@ -92,7 +92,7 @@ func (e *Engine) FilterRequest(
 }
 
 // currentEngine returns the current filtering engine.
-func (e *Engine) currentEngine() (enging *urlfilter.DNSEngine) {
+func (e *Engine) currentEngine() (engine *urlfilter.DNSEngine) {
 	e.mu.RLock()
 	defer e.mu.RUnlock()
 
@@ -103,7 +103,7 @@ func (e *Engine) currentEngine() (enging *urlfilter.DNSEngine) {
 // parseBuf, cli, cacheDir, and maxSize are used for updates of rule-list
 // filters; see [Filter.Refresh].
 //
-// TODO(a.garipov): Unexport and test in an internal test or through enigne
+// TODO(a.garipov): Unexport and test in an internal test or through engine
 // tests.
 func (e *Engine) Refresh(
 	ctx context.Context,
diff --git a/internal/filtering/rulelist/filter.go b/internal/filtering/rulelist/filter.go
index a29897de..c438748e 100644
--- a/internal/filtering/rulelist/filter.go
+++ b/internal/filtering/rulelist/filter.go
@@ -105,7 +105,7 @@ func NewFilter(c *FilterConfig) (f *Filter, err error) {
 // buffer used to parse information from the data.  cli and maxSize are only
 // used when f is a URL-based list.
 //
-// TODO(a.garipov): Unexport and test in an internal test or through enigne
+// TODO(a.garipov): Unexport and test in an internal test or through engine
 // tests.
 //
 // TODO(a.garipov): Consider not returning parseRes.
diff --git a/internal/filtering/rulelist/rulelist.go b/internal/filtering/rulelist/rulelist.go
index 021254c7..d8a82375 100644
--- a/internal/filtering/rulelist/rulelist.go
+++ b/internal/filtering/rulelist/rulelist.go
@@ -71,3 +71,10 @@ var _ fmt.Stringer = UID{}
 func (id UID) String() (s string) {
 	return uuid.UUID(id).String()
 }
+
+// Common engine names.
+const (
+	EngineNameAllow  = "allow"
+	EngineNameBlock  = "block"
+	EngineNameCustom = "custom"
+)
diff --git a/internal/filtering/rulelist/storage.go b/internal/filtering/rulelist/storage.go
index 4c35c4b3..3281032d 100644
--- a/internal/filtering/rulelist/storage.go
+++ b/internal/filtering/rulelist/storage.go
@@ -60,7 +60,7 @@ type StorageConfig struct {
 // refreshed, so a refresh should be performed before use.
 func NewStorage(c *StorageConfig) (s *Storage, err error) {
 	custom, err := NewTextEngine(&TextEngineConfig{
-		Name:  "custom",
+		Name:  EngineNameCustom,
 		Rules: c.CustomRules,
 		ID:    URLFilterIDCustom,
 	})
@@ -71,13 +71,13 @@ func NewStorage(c *StorageConfig) (s *Storage, err error) {
 	return &Storage{
 		refreshMu: &sync.Mutex{},
 		allow: NewEngine(&EngineConfig{
-			Logger:  c.Logger.With("engine", "allow"),
-			Name:    "allow",
+			Logger:  c.Logger.With("engine", EngineNameAllow),
+			Name:    EngineNameAllow,
 			Filters: c.AllowFilters,
 		}),
 		block: NewEngine(&EngineConfig{
-			Logger:  c.Logger.With("engine", "block"),
-			Name:    "block",
+			Logger:  c.Logger.With("engine", EngineNameBlock),
+			Name:    EngineNameBlock,
 			Filters: c.BlockFilters,
 		}),
 		custom:   custom,
diff --git a/internal/filtering/rulelist/storage_test.go b/internal/filtering/rulelist/storage_test.go
index b8199022..ac7e6ae3 100644
--- a/internal/filtering/rulelist/storage_test.go
+++ b/internal/filtering/rulelist/storage_test.go
@@ -41,6 +41,7 @@ func TestStorage_Refresh(t *testing.T) {
 		MaxRuleListTextSize: 1 * datasize.KB,
 	})
 	require.NoError(t, err)
+	testutil.CleanupAndRequireSuccess(t, strg.Close)
 
 	ctx := testutil.ContextWithTimeout(t, testTimeout)
 	err = strg.Refresh(ctx)
diff --git a/internal/filtering/rulelist/textengine.go b/internal/filtering/rulelist/textengine.go
index 4b5e8ce8..d04a8f5d 100644
--- a/internal/filtering/rulelist/textengine.go
+++ b/internal/filtering/rulelist/textengine.go
@@ -20,15 +20,15 @@ type TextEngine struct {
 	// storage is the filtering-rule storage.  It is saved here to close it.
 	storage *filterlist.RuleStorage
 
-	// name is the human-readable name of the engine, like "custom".
+	// name is the human-readable name of the engine.
 	name string
 }
 
 // TextEngineConfig is the configuration for a rule-list filtering engine
 // created from a filtering rule text.
 type TextEngineConfig struct {
-	// Name is the human-readable name of this engine, like "allowed",
-	// "blocked", or "custom".
+	// name is the human-readable name of the engine; see [EngineNameAllow] and
+	// similar constants.
 	Name string
 
 	// Rules is the text of the filtering rules for this engine.