Find localization entries that are not used

FindUsedKeys.cs

using System;
using System.Collections.Generic;
using System.Text;
using UnityEditor;
using UnityEditor.Localization;
using UnityEditor.SceneManagement;
using UnityEngine;
using UnityEngine.Localization.Tables;
using Object = UnityEngine.Object;

public class FindUsedKeys : ScriptableWizard
{
    HashSet<(string collectionName, long entryId)> m_FoundEntries;

    [MenuItem("Test/Find unused keys")]
    static void CreateWizard()
    {
        ScriptableWizard.DisplayWizard<FindUsedKeys>("Find unused keys", "Search");
    }

    void OnWizardCreate()
    {
        m_FoundEntries = new HashSet<(string collectionName, long entryId)> ();
        var sceneGUIDs = AssetDatabase.FindAssets("t:Scene");
        foreach (var sceneGUID in sceneGUIDs)
        {
            var path = AssetDatabase.GUIDToAssetPath(sceneGUID);
            var scene = EditorSceneManager.OpenScene(path, OpenSceneMode.Single);
            {
                foreach (var t in FindObjectsOfType<Transform>())
                {
                    foreach (var c in t.GetComponents<Component>())
                    {
                        ExtractTableReferences(c);
                    }
                }
            }
        }

        FindMissingEntries();
    }

    void FindMissingEntries()
    {
        var sb = new StringBuilder();
        foreach(var collection in LocalizationEditorSettings.GetStringTableCollections())
        {
            foreach(var entry in collection.SharedData.Entries)
            {
                if (m_FoundEntries.Contains((collection.TableCollectionName, entry.Id)))
                {
                    // Entry is used
                    sb.AppendLine($"USED - {collection.TableCollectionName} / {entry.Key}");
                }
                else
                {
                    // Entry is not used.
                    sb.AppendLine($"NOT USED - {collection.TableCollectionName} / {entry.Key}");
                }
            }
        }

        Debug.Log(sb.ToString());
    }

    void ExtractTableReferences(Object unityObject)
    {
        var so = new SerializedObject(unityObject);
        var itr = so.GetIterator();
        while (itr.Next(true))
        {
            if (itr.type == "LocalizedString")
            {
                var collectionNameProperty = itr.FindPropertyRelative("m_TableReference.m_TableCollectionName");
                var collectionName = collectionNameProperty.stringValue;

                TableReference tableReference;
                if (collectionName.StartsWith("GUID:"))
                    tableReference = Guid.Parse(collectionName.Substring("GUID:".Length, collectionName.Length -  "GUID:".Length));
                else
                    tableReference = collectionName;

                var key = itr.FindPropertyRelative("m_TableEntryReference.m_Key");
                var keyId = itr.FindPropertyRelative("m_TableEntryReference.m_KeyId");
                TableEntryReference tableEntryReference;
                if (keyId.longValue == 0)
                    tableEntryReference = key.stringValue;
                else
                    tableEntryReference = keyId.longValue;

                var collection = LocalizationEditorSettings.GetStringTableCollection(tableReference);
                var stringTableEntry = collection?.SharedData.GetEntryFromReference(tableEntryReference);
                if (stringTableEntry != null)
                {
                    m_FoundEntries.Add((collection.TableCollectionName, stringTableEntry.Id));
                }
            }
        }
    }
}