diff --git a/apps/openmw/mwbase/world.hpp b/apps/openmw/mwbase/world.hpp
index db2f1fe338..e3bf06a10f 100644
--- a/apps/openmw/mwbase/world.hpp
+++ b/apps/openmw/mwbase/world.hpp
@@ -660,8 +660,7 @@ namespace MWBase
         virtual DetourNavigator::Navigator* getNavigator() const = 0;
 
         virtual void updateActorPath(const MWWorld::ConstPtr& actor, const std::deque<osg::Vec3f>& path,
-            const DetourNavigator::AgentBounds& agentBounds, const osg::Vec3f& start, const osg::Vec3f& end) const
-            = 0;
+            const DetourNavigator::AgentBounds& agentBounds, const osg::Vec3f& start, const osg::Vec3f& end) const = 0;
 
         virtual void removeActorPath(const MWWorld::ConstPtr& actor) const = 0;
 
@@ -670,12 +669,10 @@ namespace MWBase
         virtual DetourNavigator::AgentBounds getPathfindingAgentBounds(const MWWorld::ConstPtr& actor) const = 0;
 
         virtual bool hasCollisionWithDoor(
-            const MWWorld::ConstPtr& door, const osg::Vec3f& position, const osg::Vec3f& destination) const
-            = 0;
+            const MWWorld::ConstPtr& door, const osg::Vec3f& position, const osg::Vec3f& destination) const = 0;
 
         virtual bool isAreaOccupiedByOtherActor(const osg::Vec3f& position, const float radius,
-            std::span<const MWWorld::ConstPtr> ignore, std::vector<MWWorld::Ptr>* occupyingActors = nullptr) const
-            = 0;
+            std::span<const MWWorld::ConstPtr> ignore, std::vector<MWWorld::Ptr>* occupyingActors = nullptr) const = 0;
 
         virtual void reportStats(unsigned int frameNumber, osg::Stats& stats) const = 0;
 
diff --git a/apps/openmw/mwgui/birth.cpp b/apps/openmw/mwgui/birth.cpp
index ed82a80507..c60a3e1ca5 100644
--- a/apps/openmw/mwgui/birth.cpp
+++ b/apps/openmw/mwgui/birth.cpp
@@ -96,7 +96,7 @@ namespace MWGui
         size_t count = mBirthList->getItemCount();
         for (size_t i = 0; i < count; ++i)
         {
-            if (ESM::RefId::stringRefId(*mBirthList->getItemDataAt<std::string>(i)) == birthId)
+            if (*mBirthList->getItemDataAt<ESM::RefId>(i) == birthId)
             {
                 mBirthList->setIndexSelected(i);
                 break;
@@ -133,7 +133,7 @@ namespace MWGui
         if (_index == MyGUI::ITEM_NONE)
             return;
 
-        const ESM::RefId birthId = ESM::RefId::stringRefId(*mBirthList->getItemDataAt<std::string>(_index));
+        const ESM::RefId& birthId = *mBirthList->getItemDataAt<ESM::RefId>(_index);
         if (mCurrentBirthId == birthId)
             return;
 
diff --git a/apps/openmw/mwgui/race.cpp b/apps/openmw/mwgui/race.cpp
index b90ff9a10a..54ab302f67 100644
--- a/apps/openmw/mwgui/race.cpp
+++ b/apps/openmw/mwgui/race.cpp
@@ -191,7 +191,7 @@ namespace MWGui
         size_t count = mRaceList->getItemCount();
         for (size_t i = 0; i < count; ++i)
         {
-            if (ESM::RefId::stringRefId(*mRaceList->getItemDataAt<std::string>(i)) == raceId)
+            if (*mRaceList->getItemDataAt<ESM::RefId>(i) == raceId)
             {
                 mRaceList->setIndexSelected(i);
                 break;
@@ -292,7 +292,7 @@ namespace MWGui
         if (_index == MyGUI::ITEM_NONE)
             return;
 
-        ESM::RefId raceId = ESM::RefId::stringRefId(*mRaceList->getItemDataAt<std::string>(_index));
+        ESM::RefId& raceId = *mRaceList->getItemDataAt<ESM::RefId>(_index);
         if (mCurrentRaceId == raceId)
             return;
 
diff --git a/apps/openmw/mwmechanics/character.cpp b/apps/openmw/mwmechanics/character.cpp
index 2a54152442..2ad1c91e28 100644
--- a/apps/openmw/mwmechanics/character.cpp
+++ b/apps/openmw/mwmechanics/character.cpp
@@ -1029,7 +1029,7 @@ namespace MWMechanics
                 }
             }
 
-            auto sound = charClass.getSoundIdFromSndGen(mPtr, soundgen);
+            const auto& sound = charClass.getSoundIdFromSndGen(mPtr, soundgen);
             if (!sound.empty())
             {
                 MWBase::SoundManager* sndMgr = MWBase::Environment::get().getSoundManager();
@@ -2043,7 +2043,7 @@ namespace MWMechanics
                 if (!godmode)
                 {
                     // reduce fatigue
-                    float fatigueLoss = 0;
+                    float fatigueLoss = 0.f;
                     static const float fFatigueRunBase = gmst.find("fFatigueRunBase")->mValue.getFloat();
                     static const float fFatigueRunMult = gmst.find("fFatigueRunMult")->mValue.getFloat();
                     static const float fFatigueSwimWalkBase = gmst.find("fFatigueSwimWalkBase")->mValue.getFloat();
@@ -2159,7 +2159,6 @@ namespace MWMechanics
                     if (mPtr.getClass().isNpc())
                     {
                         std::string_view sound;
-
                         osg::Vec3f pos(mPtr.getRefData().getPosition().asVec3());
                         if (world->isUnderwater(mPtr.getCell(), pos) || world->isWalkingOnWater(mPtr))
                             sound = "DefaultLandWater";
diff --git a/apps/openmw/mwmechanics/levelledlist.hpp b/apps/openmw/mwmechanics/levelledlist.hpp
index f9ad488607..d499649944 100644
--- a/apps/openmw/mwmechanics/levelledlist.hpp
+++ b/apps/openmw/mwmechanics/levelledlist.hpp
@@ -44,7 +44,7 @@ namespace MWMechanics
         if (creature)
             allLevels = levItem->mFlags & ESM::CreatureLevList::AllLevels;
 
-        std::pair<int, const ESM::RefId*> highest = { -1, {} };
+        std::pair<int, const ESM::RefId*> highest = { -1, nullptr };
         for (const auto& levelledItem : items)
         {
             if (playerLevel >= levelledItem.mLevel && (allLevels || levelledItem.mLevel == highestLevel))
diff --git a/apps/openmw/mwmechanics/mechanicsmanagerimp.cpp b/apps/openmw/mwmechanics/mechanicsmanagerimp.cpp
index 92c6d1990f..2310e00920 100644
--- a/apps/openmw/mwmechanics/mechanicsmanagerimp.cpp
+++ b/apps/openmw/mwmechanics/mechanicsmanagerimp.cpp
@@ -524,7 +524,7 @@ namespace MWMechanics
 
         float reaction = 0;
         int rank = 0;
-        ESM::RefId npcFaction = ptr.getClass().getPrimaryFaction(ptr);
+        const ESM::RefId& npcFaction = ptr.getClass().getPrimaryFaction(ptr);
 
         if (playerStats.getFactionRanks().find(npcFaction) != playerStats.getFactionRanks().end())
         {
diff --git a/apps/openmw/mwrender/weaponanimation.cpp b/apps/openmw/mwrender/weaponanimation.cpp
index a356545ce5..a6f069e932 100644
--- a/apps/openmw/mwrender/weaponanimation.cpp
+++ b/apps/openmw/mwrender/weaponanimation.cpp
@@ -69,7 +69,7 @@ namespace MWRender
         ESM::WeaponType::Class weapclass = MWMechanics::getWeaponType(type)->mWeaponClass;
         if (weapclass == ESM::WeaponType::Thrown)
         {
-            auto soundid = weaponSlot->getClass().getUpSoundId(*weaponSlot);
+            const auto& soundid = weaponSlot->getClass().getUpSoundId(*weaponSlot);
             if (!soundid.empty())
             {
                 MWBase::SoundManager* sndMgr = MWBase::Environment::get().getSoundManager();
diff --git a/apps/openmw/mwworld/containerstore.cpp b/apps/openmw/mwworld/containerstore.cpp
index 38847515ba..d31b7896ee 100644
--- a/apps/openmw/mwworld/containerstore.cpp
+++ b/apps/openmw/mwworld/containerstore.cpp
@@ -485,7 +485,7 @@ void MWWorld::ContainerStore::updateRechargingItems()
     mRechargingItems.clear();
     for (ContainerStoreIterator it = begin(); it != end(); ++it)
     {
-        auto enchantmentId = it->getClass().getEnchantment(*it);
+        const auto& enchantmentId = it->getClass().getEnchantment(*it);
         if (!enchantmentId.empty())
         {
             const ESM::Enchantment* enchantment
diff --git a/apps/openmw/mwworld/worldmodel.cpp b/apps/openmw/mwworld/worldmodel.cpp
index df26abe14a..99402c1e35 100644
--- a/apps/openmw/mwworld/worldmodel.cpp
+++ b/apps/openmw/mwworld/worldmodel.cpp
@@ -62,10 +62,11 @@ MWWorld::CellStore* MWWorld::WorldModel::getCellStore(const ESM::Cell* cell)
 {
     if (cell->mData.mFlags & ESM::Cell::Interior)
     {
-        auto result = mInteriors.find(cell->mName);
+        std::string lowerName(Misc::StringUtils::lowerCase(cell->mName));
+        auto result = mInteriors.find(lowerName);
 
         if (result == mInteriors.end())
-            result = mInteriors.emplace(std::move(cell->mName), CellStore(cell, mStore, mReaders)).first;
+            result = mInteriors.emplace(std::move(lowerName), CellStore(cell, mStore, mReaders)).first;
 
         return &result->second;
     }
@@ -171,13 +172,14 @@ MWWorld::CellStore* MWWorld::WorldModel::getExterior(int x, int y)
 
 MWWorld::CellStore* MWWorld::WorldModel::getInterior(std::string_view name)
 {
-    auto result = mInteriors.find(std::string(name));
+    std::string lowerName = Misc::StringUtils::lowerCase(name);
+    auto result = mInteriors.find(lowerName);
 
     if (result == mInteriors.end())
     {
         const ESM::Cell* cell = mStore.get<ESM::Cell>().find(ESM::RefId::stringRefId(name));
 
-        result = mInteriors.emplace(std::move(name), CellStore(cell, mStore, mReaders)).first;
+        result = mInteriors.emplace(lowerName, CellStore(cell, mStore, mReaders)).first;
     }
 
     if (result->second.getState() != CellStore::State_Loaded)
diff --git a/components/compiler/exprparser.cpp b/components/compiler/exprparser.cpp
index 363d68c30d..bd4e722205 100644
--- a/components/compiler/exprparser.cpp
+++ b/components/compiler/exprparser.cpp
@@ -205,7 +205,7 @@ namespace Compiler
         mMemberOp = false;
 
         std::string name2 = Misc::StringUtils::lowerCase(name);
-        auto id = ESM::RefId::stringRefId(mExplicit);
+        auto id = ESM::RefId::stringRefId(Misc::StringUtils::lowerCase(mExplicit));
 
         std::pair<char, bool> type = getContext().getMemberType(name2, id);
 
@@ -303,29 +303,31 @@ namespace Compiler
         {
             start();
 
-            char type = mLocals.getType(name);
+            std::string name2 = Misc::StringUtils::lowerCase(name);
+
+            char type = mLocals.getType(name2);
 
             if (type != ' ')
             {
-                Generator::fetchLocal(mCode, type, mLocals.getIndex(name));
+                Generator::fetchLocal(mCode, type, mLocals.getIndex(name2));
                 mNextOperand = false;
                 mOperands.push_back(type == 'f' ? 'f' : 'l');
                 return true;
             }
 
-            type = getContext().getGlobalType(name);
+            type = getContext().getGlobalType(name2);
 
             if (type != ' ')
             {
-                Generator::fetchGlobal(mCode, mLiterals, type, name);
+                Generator::fetchGlobal(mCode, mLiterals, type, name2);
                 mNextOperand = false;
                 mOperands.push_back(type == 'f' ? 'f' : 'l');
                 return true;
             }
 
-            if (mExplicit.empty() && getContext().isId(ESM::RefId::stringRefId(name)))
+            if (mExplicit.empty() && getContext().isId(ESM::RefId::stringRefId(name2)))
             {
-                mExplicit = name;
+                mExplicit = name2;
                 return true;
             }
 
@@ -333,7 +335,7 @@ namespace Compiler
             // Convert the string to a number even if it's impossible and use it as a number literal.
             // Can't use stof/atof or to_string out of locale concerns.
             float number;
-            std::stringstream stream(name);
+            std::stringstream stream(name2);
             stream >> number;
             stream.str(std::string());
             stream.clear();
diff --git a/components/compiler/streamerrorhandler.cpp b/components/compiler/streamerrorhandler.cpp
index b198cf05d1..e72eb6fdb1 100644
--- a/components/compiler/streamerrorhandler.cpp
+++ b/components/compiler/streamerrorhandler.cpp
@@ -3,7 +3,6 @@
 #include <sstream>
 
 #include <components/debug/debuglog.hpp>
-#include <components/esm/refid.hpp>
 
 #include "tokenloc.hpp"
 
diff --git a/components/interpreter/defines.cpp b/components/interpreter/defines.cpp
index 64090fb9b8..0fd0157425 100644
--- a/components/interpreter/defines.cpp
+++ b/components/interpreter/defines.cpp
@@ -214,7 +214,6 @@ namespace Interpreter
                         if (globals.empty())
                         {
                             globals = context.getGlobals();
-                            ;
                             sort(globals.begin(), globals.end(), longerStr);
                         }