diff --git a/packages/frontend/src/components/MkAchievements.vue b/packages/frontend/src/components/MkAchievements.vue
index 70766634ce..3b7b59b4d3 100644
--- a/packages/frontend/src/components/MkAchievements.vue
+++ b/packages/frontend/src/components/MkAchievements.vue
@@ -71,7 +71,7 @@ const props = withDefaults(defineProps<{
 const achievements = ref<Misskey.entities.UsersAchievementsResponse | null>(null);
 const lockedAchievements = computed(() => ACHIEVEMENT_TYPES.filter(x => !(achievements.value ?? []).some(a => a.name === x)));
 
-function fetch() {
+function _fetch_() {
 	misskeyApi('users/achievements', { userId: props.user.id }).then(res => {
 		achievements.value = [];
 		for (const t of ACHIEVEMENT_TYPES) {
@@ -84,11 +84,11 @@ function fetch() {
 
 function clickHere() {
 	claimAchievement('clickedClickHere');
-	fetch();
+	_fetch_();
 }
 
 onMounted(() => {
-	fetch();
+	_fetch_();
 });
 </script>
 
diff --git a/packages/frontend/src/components/MkAnimBg.vue b/packages/frontend/src/components/MkAnimBg.vue
index 82606c9aa4..19a21f6e24 100644
--- a/packages/frontend/src/components/MkAnimBg.vue
+++ b/packages/frontend/src/components/MkAnimBg.vue
@@ -265,6 +265,8 @@ onUnmounted(() => {
 	if (handle) {
 		window.cancelAnimationFrame(handle);
 	}
+
+	// TODO: WebGLリソースの解放
 });
 </script>
 
diff --git a/packages/frontend/src/pages/admin-file.vue b/packages/frontend/src/pages/admin-file.vue
index 7a49ba542f..90b3ca81cf 100644
--- a/packages/frontend/src/pages/admin-file.vue
+++ b/packages/frontend/src/pages/admin-file.vue
@@ -111,13 +111,13 @@ const props = defineProps<{
 	fileId: string,
 }>();
 
-async function fetch() {
+async function _fetch_() {
 	file.value = await misskeyApi('drive/files/show', { fileId: props.fileId });
 	info.value = await misskeyApi('admin/drive/show-file', { fileId: props.fileId });
 	isSensitive.value = file.value.isSensitive;
 }
 
-fetch();
+_fetch_();
 
 async function del() {
 	const { canceled } = await os.confirm({
diff --git a/packages/frontend/src/pages/announcement.vue b/packages/frontend/src/pages/announcement.vue
index f9b870eda1..0bcfd28f67 100644
--- a/packages/frontend/src/pages/announcement.vue
+++ b/packages/frontend/src/pages/announcement.vue
@@ -39,7 +39,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 					<MkButton primary @click="read(announcement)"><i class="ti ti-check"></i> {{ i18n.ts.gotIt }}</MkButton>
 				</div>
 			</div>
-			<MkError v-else-if="error" @retry="fetch()"/>
+			<MkError v-else-if="error" @retry="_fetch_()"/>
 			<MkLoading v-else/>
 		</Transition>
 	</div>
@@ -66,7 +66,7 @@ const announcement = ref<Misskey.entities.Announcement | null>(null);
 const error = ref<any>(null);
 const path = computed(() => props.announcementId);
 
-function fetch() {
+function _fetch_() {
 	announcement.value = null;
 	misskeyApi('announcements/show', {
 		announcementId: props.announcementId,
@@ -96,7 +96,7 @@ async function read(target: Misskey.entities.Announcement): Promise<void> {
 	}
 }
 
-watch(() => path.value, fetch, { immediate: true });
+watch(() => path.value, _fetch_, { immediate: true });
 
 const headerActions = computed(() => []);
 
diff --git a/packages/frontend/src/pages/drive.file.info.vue b/packages/frontend/src/pages/drive.file.info.vue
index 1def215afc..79c249413a 100644
--- a/packages/frontend/src/pages/drive.file.info.vue
+++ b/packages/frontend/src/pages/drive.file.info.vue
@@ -105,7 +105,7 @@ const folderHierarchy = computed(() => {
 });
 const isImage = computed(() => file.value?.type.startsWith('image/'));
 
-async function fetch() {
+async function _fetch_() {
 	fetching.value = true;
 
 	file.value = await misskeyApi('drive/files/show', {
@@ -134,7 +134,7 @@ function move() {
 			fileId: file.value.id,
 			folderId: folder[0] ? folder[0].id : null,
 		}).then(async () => {
-			await fetch();
+			await _fetch_();
 		});
 	});
 }
@@ -146,7 +146,7 @@ function toggleSensitive() {
 		fileId: file.value.id,
 		isSensitive: !file.value.isSensitive,
 	}).then(async () => {
-		await fetch();
+		await _fetch_();
 	}).catch(err => {
 		os.alert({
 			type: 'error',
@@ -169,7 +169,7 @@ function rename() {
 			fileId: file.value.id,
 			name: name,
 		}).then(async () => {
-			await fetch();
+			await _fetch_();
 		});
 	});
 }
@@ -186,7 +186,7 @@ async function describe() {
 				fileId: file.value.id,
 				comment: caption.length === 0 ? null : caption,
 			}).then(async () => {
-				await fetch();
+				await _fetch_();
 			});
 		},
 		closed: () => dispose(),
@@ -212,7 +212,7 @@ async function deleteFile() {
 }
 
 onMounted(async () => {
-	await fetch();
+	await _fetch_();
 });
 </script>
 
diff --git a/packages/frontend/src/pages/install-extensions.vue b/packages/frontend/src/pages/install-extensions.vue
index 1b3c6616cc..4b87e0da6b 100644
--- a/packages/frontend/src/pages/install-extensions.vue
+++ b/packages/frontend/src/pages/install-extensions.vue
@@ -80,7 +80,7 @@ function close_(): void {
 	}
 }
 
-async function fetch() {
+async function _fetch_() {
 	if (!url.value || !hash.value) {
 		errorKV.value = {
 			title: i18n.ts._externalResourceInstaller._errors._invalidParams.title,
@@ -229,7 +229,7 @@ async function install() {
 const urlParams = new URLSearchParams(window.location.search);
 url.value = urlParams.get('url');
 hash.value = urlParams.get('hash');
-fetch();
+_fetch_();
 
 definePage(() => ({
 	title: i18n.ts._externalResourceInstaller.title,
diff --git a/packages/frontend/src/pages/instance-info.vue b/packages/frontend/src/pages/instance-info.vue
index 4be5fa447d..473207fe6e 100644
--- a/packages/frontend/src/pages/instance-info.vue
+++ b/packages/frontend/src/pages/instance-info.vue
@@ -198,7 +198,7 @@ if (iAmModerator) {
 	});
 }
 
-async function fetch(): Promise<void> {
+async function _fetch_(): Promise<void> {
 	if (iAmAdmin) {
 		meta.value = await misskeyApi('admin/meta');
 	}
@@ -276,7 +276,7 @@ function refreshMetadata(): void {
 	});
 }
 
-fetch();
+_fetch_();
 
 const headerActions = computed(() => [{
 	text: `https://${props.host}`,
diff --git a/packages/frontend/src/pages/my-antennas/index.vue b/packages/frontend/src/pages/my-antennas/index.vue
index 95a3108e3a..d7625a8a1c 100644
--- a/packages/frontend/src/pages/my-antennas/index.vue
+++ b/packages/frontend/src/pages/my-antennas/index.vue
@@ -30,11 +30,11 @@ import { antennasCache } from '@/cache.js';
 
 const antennas = computed(() => antennasCache.value.value ?? []);
 
-function fetch() {
+function _fetch_() {
 	antennasCache.fetch();
 }
 
-fetch();
+_fetch_();
 
 const headerActions = computed(() => [{
 	asFullButton: true,
@@ -42,7 +42,7 @@ const headerActions = computed(() => [{
 	text: i18n.ts.reload,
 	handler: () => {
 		antennasCache.delete();
-		fetch();
+		_fetch_();
 	},
 }]);
 
diff --git a/packages/frontend/src/pages/my-lists/index.vue b/packages/frontend/src/pages/my-lists/index.vue
index 0933618f54..43d5432f66 100644
--- a/packages/frontend/src/pages/my-lists/index.vue
+++ b/packages/frontend/src/pages/my-lists/index.vue
@@ -40,11 +40,11 @@ const $i = ensureSignin();
 
 const items = computed(() => userListsCache.value.value ?? []);
 
-function fetch() {
+function _fetch_() {
 	userListsCache.fetch();
 }
 
-fetch();
+_fetch_();
 
 async function create() {
 	const { canceled, result: name } = await os.inputText({
@@ -53,7 +53,7 @@ async function create() {
 	if (canceled || name == null) return;
 	await os.apiWithDialog('users/lists/create', { name: name });
 	userListsCache.delete();
-	fetch();
+	_fetch_();
 }
 
 const headerActions = computed(() => [{
@@ -62,7 +62,7 @@ const headerActions = computed(() => [{
 	text: i18n.ts.reload,
 	handler: () => {
 		userListsCache.delete();
-		fetch();
+		_fetch_();
 	},
 }]);
 
@@ -74,7 +74,7 @@ definePage(() => ({
 }));
 
 onActivated(() => {
-	fetch();
+	_fetch_();
 });
 </script>
 
diff --git a/packages/frontend/src/pages/settings/index.vue b/packages/frontend/src/pages/settings/index.vue
index eda9dfde7b..250c1735be 100644
--- a/packages/frontend/src/pages/settings/index.vue
+++ b/packages/frontend/src/pages/settings/index.vue
@@ -188,6 +188,8 @@ const menuDef = computed<SuperMenuDef[]>(() => [{
 }]);
 
 onMounted(() => {
+	if (el.value == null) return; // TSを黙らすため
+
 	ro.observe(el.value);
 
 	narrow.value = el.value.offsetWidth < NARROW_THRESHOLD;
@@ -198,6 +200,8 @@ onMounted(() => {
 });
 
 onActivated(() => {
+	if (el.value == null) return; // TSを黙らすため
+
 	narrow.value = el.value.offsetWidth < NARROW_THRESHOLD;
 
 	if (!narrow.value && currentPage.value?.route.name == null) {
@@ -215,7 +219,7 @@ watch(router.currentRef, (to) => {
 	}
 });
 
-const emailNotConfigured = computed(() => instance.enableEmail && ($i.email == null || !$i.emailVerified));
+const emailNotConfigured = computed(() => $i && instance.enableEmail && ($i.email == null || !$i.emailVerified));
 
 provideMetadataReceiver((metadataGetter) => {
 	const info = metadataGetter();
diff --git a/packages/frontend/src/pages/settings/profile.vue b/packages/frontend/src/pages/settings/profile.vue
index e2679623ef..4816a6e33b 100644
--- a/packages/frontend/src/pages/settings/profile.vue
+++ b/packages/frontend/src/pages/settings/profile.vue
@@ -7,7 +7,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 <SearchMarker path="/settings/profile" :label="i18n.ts.profile" :keywords="['profile']" icon="ti ti-user">
 	<div class="_gaps_m">
 		<div class="_panel">
-			<div :class="$style.banner" :style="{ backgroundImage: $i.bannerUrl ? `url(${ $i.bannerUrl })` : null }">
+			<div :class="$style.banner" :style="{ backgroundImage: $i.bannerUrl ? `url(${ $i.bannerUrl })` : '' }">
 				<div :class="$style.bannerEdit">
 					<SearchMarker :keywords="['banner', 'change']">
 						<MkButton primary rounded @click="changeBanner"><SearchLabel>{{ i18n.ts._profile.changeBanner }}</SearchLabel></MkButton>
diff --git a/packages/frontend/src/pages/settings/theme.install.vue b/packages/frontend/src/pages/settings/theme.install.vue
index ac95279402..f79357c361 100644
--- a/packages/frontend/src/pages/settings/theme.install.vue
+++ b/packages/frontend/src/pages/settings/theme.install.vue
@@ -10,8 +10,8 @@ SPDX-License-Identifier: AGPL-3.0-only
 	</MkCodeEditor>
 
 	<div class="_buttons">
-		<MkButton :disabled="installThemeCode == null || installThemeCode.trim() === ''" inline @click="() => previewTheme(installThemeCode)"><i class="ti ti-eye"></i> {{ i18n.ts.preview }}</MkButton>
-		<MkButton :disabled="installThemeCode == null || installThemeCode.trim() === ''" primary inline @click="() => install(installThemeCode)"><i class="ti ti-check"></i> {{ i18n.ts.install }}</MkButton>
+		<MkButton :disabled="installThemeCode == null || installThemeCode.trim() === ''" inline @click="() => previewTheme(installThemeCode!)"><i class="ti ti-eye"></i> {{ i18n.ts.preview }}</MkButton>
+		<MkButton :disabled="installThemeCode == null || installThemeCode.trim() === ''" primary inline @click="() => install(installThemeCode!)"><i class="ti ti-check"></i> {{ i18n.ts.install }}</MkButton>
 	</div>
 </div>
 </template>
@@ -39,7 +39,7 @@ async function install(code: string): Promise<void> {
 		});
 		installThemeCode.value = null;
 		router.push('/settings/theme');
-	} catch (err) {
+	} catch (err: any) {
 		switch (err.message.toLowerCase()) {
 			case 'this theme is already installed':
 				os.alert({
diff --git a/packages/frontend/src/pages/settings/theme.manage.vue b/packages/frontend/src/pages/settings/theme.manage.vue
index fcd0b293e0..e972184278 100644
--- a/packages/frontend/src/pages/settings/theme.manage.vue
+++ b/packages/frontend/src/pages/settings/theme.manage.vue
@@ -25,7 +25,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 			<template #label>{{ i18n.ts._theme.code }}</template>
 			<template #caption><button class="_textButton" @click="copyThemeCode()">{{ i18n.ts.copy }}</button></template>
 		</MkTextarea>
-		<MkButton v-if="!builtinThemes.some(t => t.id == selectedTheme.id)" danger @click="uninstall()"><i class="ti ti-trash"></i> {{ i18n.ts.uninstall }}</MkButton>
+		<MkButton v-if="!builtinThemes.some(t => t.id == selectedTheme!.id)" danger @click="uninstall()"><i class="ti ti-trash"></i> {{ i18n.ts.uninstall }}</MkButton>
 	</template>
 </div>
 </template>
diff --git a/packages/frontend/src/theme.ts b/packages/frontend/src/theme.ts
index 036b86cff8..b715426917 100644
--- a/packages/frontend/src/theme.ts
+++ b/packages/frontend/src/theme.ts
@@ -23,6 +23,7 @@ export type Theme = {
 	author: string;
 	desc?: string;
 	base?: 'dark' | 'light';
+	kind?: 'dark' | 'light'; // legacy
 	props: Record<string, string>;
 	codeHighlighter?: {
 		base: BundledTheme;