diff --git a/.requirements/configure.mk b/.requirements/configure.mk
index 79288532..c5d7376d 100644
--- a/.requirements/configure.mk
+++ b/.requirements/configure.mk
@@ -2,6 +2,9 @@
 .PHONY: configure.harden
 configure.harden:  ## Harden local configuration
 	sudo ufw enable || true
+	sudo ufw allow ssh comment 'ssh' || true
+	sudo ufw allow proto tcp from 192.168.0.0/24 port 24800 to 192.168.0.0/24 port 24800 comment 'barrier-kvm' || true
+	sudo ufw allow proto tcp from port 8123 to port 8123 comment 'home-assistant' || true
 	sudo systemctl disable lightdm.service || true
 	sudo systemctl disable lightdm || true
 	sudo systemctl set-default multi-user.target || true
diff --git a/.requirements/firefox.txt b/.requirements/firefox.txt
index 9e44cc39..8ddb4d9f 100644
--- a/.requirements/firefox.txt
+++ b/.requirements/firefox.txt
@@ -1,14 +1,25 @@
-https://s3.amazonaws.com/onelogin-downloads/extensions/firefox/onelogin.xpi
-https://addons.mozilla.org/firefox/downloads/file/3657084/lastpass_password_manager-4.58.0.4-an+fx.xpi
-# https://addons.mozilla.org/firefox/downloads/file/3492484/tree_style_tab_-3.3.5-fx.xpi
-# https://addons.mozilla.org/firefox/downloads/file/3484647/privacy_badger-2020.1.13-an+fx.xpi
+# Broken
+# https://addons.mozilla.org/firefox/downloads/file/3502765/vimium_ff-1.65.1-fx.xpi
+# https://addons.mozilla.org/firefox/downloads/file/3500160/dark_reader-4.8.9-an+fx.xpi
 # https://addons.mozilla.org/firefox/downloads/file/3474268/ghostery_privacy_ad_blocker-8.4.6-an+fx.xpi
-# https://addons.mozilla.org/firefox/downloads/file/3498086/ublock_origin-1.24.4-an+fx.xpi
+
+# Not installed
+# https://s3.amazonaws.com/onelogin-downloads/extensions/firefox/onelogin.xpi
+# https://addons.mozilla.org/firefox/downloads/file/3657084/lastpass_password_manager-4.58.0.4-an+fx.xpi
 # https://addons.mozilla.org/firefox/downloads/file/3054598/video_downloadhelper-7.3.7-fx.xpi
 # https://addons.mozilla.org/firefox/downloads/file/3442258/https_everywhere-2019.11.7-an+fx.xpi
-# https://addons.mozilla.org/firefox/downloads/file/3500160/dark_reader-4.8.9-an+fx.xpi
-# https://addons.mozilla.org/firefox/downloads/file/3401561/stylus-1.5.6-fx.xpi
+# https://addons.mozilla.org/firefox/downloads/file/3384741/remove_fbclid_and_utm-1.0-fx.xpi
+
+# Installed
+# https://addons.mozilla.org/firefox/downloads/file/3484647/privacy_badger-2020.1.13-an+fx.xpi
+# https://addons.mozilla.org/firefox/downloads/file/3498086/ublock_origin-1.24.4-an+fx.xpi
 # https://addons.mozilla.org/firefox/downloads/file/3495605/noscript_security_suite-11.0.13-an+fx.xpi
-# https://addons.mozilla.org/firefox/downloads/file/3502765/vimium_ff-1.65.1-fx.xpi
 # https://addons.mozilla.org/firefox/downloads/file/3401561/stylus-1.5.6-fx.xpi
-# https://addons.mozilla.org/firefox/downloads/file/3384741/remove_fbclid_and_utm-1.0-fx.xpi
+# https://addons.mozilla.org/firefox/downloads/file/3884195/sidebery-4.10.0-fx.xpi
+# https://addons.mozilla.org/firefox/downloads/file/3594370/epubreader-2.0.13-fx.xpi
+# https://addons.mozilla.org/firefox/downloads/file/3904618/dark_reader-4.9.45-an+fx.xpi
+https://addons.mozilla.org/firefox/downloads/file/3811501/tab_reloader_page_auto_refresh-0.3.7-fx.xpi
+https://addons.mozilla.org/firefox/downloads/file/3898202/vimium_ff-1.67.1-fx.xpi
+https://addons.mozilla.org/firefox/downloads/file/3907697/firefox_multi_account_containers-8.0.6-fx.xpi
+https://addons.mozilla.org/firefox/downloads/file/3723251/temporary_containers-1.9.2-fx.xpi
+https://addons.mozilla.org/firefox/downloads/file/3897820/i_dont_care_about_cookies-3.3.6-an+fx.xpi
diff --git a/.requirements/lint.mk b/.requirements/lint.mk
index 6775c713..2715860f 100644
--- a/.requirements/lint.mk
+++ b/.requirements/lint.mk
@@ -44,19 +44,30 @@ FIND_FILES_ALL=( \
 LINT_SH_ALL=$(FIND_FILES_ALL) | $(XARGS_SHELLCHECK)
 XARGS_SHELLCHECK = xargs -0 --no-run-if-empty shellcheck --external-sources
 
-AWK_LINT=$(shell command -v awk-lint >/dev/null 2>&1 && echo awk-lint || echo "echo '\n\ta b c\td ef\n\ng' | awk -f")
-AWK_FILES=$(shell grep \
-    --recursive \
-    --files-with-match \
-    '^\#!\/usr\/bin\/awk' \
-)
+ifneq (,$(wildcard utils/.local/bin/awk-lint))
+AWK_LINT=utils/.local/bin/awk-lint
+else ifneq (,$(shell command -v awk-lint 2>/dev/null))
+AWK_LINT=awk-lint
+endif
 
 .PHONY: lint-awk
 lint-awk: $(AWK_FILES)
-
-.PHONY: $(AWK_FILES)
-$(AWK_FILES):
-	@$(AWK_LINT) "$(@)"
+ifeq (,$(AWK_LINT))
+	@echo "Helper script 'lint-awk' missing; cannot continue."
+	@exit 1
+else
+	grep \
+		--recursive \
+		--binary-files=without-match \
+		--files-with-match \
+		'^\#!\/usr\/bin\/awk' \
+		--null \
+	| xargs -0 \
+		-n 1 \
+		--no-run-if-empty \
+		$(AWK_LINT) \
+	;
+endif
 
 .PHONY: lint
 lint: lint-awk  ## Run the linter against all files
diff --git a/shells/.config/ssh/config b/shells/.config/ssh/config
index ac8879d5..23a2fbea 100755
--- a/shells/.config/ssh/config
+++ b/shells/.config/ssh/config
@@ -1,5 +1,6 @@
 Include ~/.local/share/ssh/config
 
 Host *
-    IdentityFile ~/.local/share/ssh/keys/id_rsa
+    AddKeysToAgent yes
+    IdentityFile ~/.config/ssh/keys/id_rsa
     UserKnownHostsFile ~/.cache/ssh_known_hosts
diff --git a/shells/.config/user-dirs.dirs b/shells/.config/user-dirs.dirs
index 1b51271d..570e2d72 100644
--- a/shells/.config/user-dirs.dirs
+++ b/shells/.config/user-dirs.dirs
@@ -11,8 +11,8 @@ XDG_DESKTOP_DIR="$HOME/.local/share/desktop"
 XDG_DOWNLOAD_DIR="$HOME/.local/share/downloads"
 XDG_TEMPLATES_DIR="$HOME/.config/templates"
 XDG_PUBLICSHARE_DIR="$HOME/.local/share/public"
-XDG_DOCUMENTS_DIR="$HOME/media/documents"
-XDG_MUSIC_DIR="$HOME/media/audio/music"
-XDG_PICTURES_DIR="$HOME/media/pictures"
+XDG_DOCUMENTS_DIR="$HOME/library/document"
+XDG_MUSIC_DIR="$HOME/library/audio/music"
+XDG_PICTURES_DIR="$HOME/library/image"
 XDG_STATE_HOME="$HOME/.local/var"
-XDG_VIDEOS_DIR="$HOME/media/video"
+XDG_VIDEOS_DIR="$HOME/library/video"
diff --git a/shells/.local/bin/firefox b/shells/.local/bin/firefox
new file mode 100755
index 00000000..47f4f43d
--- /dev/null
+++ b/shells/.local/bin/firefox
@@ -0,0 +1,5 @@
+#!/bin/sh
+_command=$(command-shadowed -v "${0}")
+private_directory="${XDG_CONFIG_HOME:-${HOME}/.config}/mozilla"
+[ -d "${private_directory}" ] || mkdir -p "${private_directory}"
+firejail --private="${private_directory}" "${_command}" "${@}"
diff --git a/shells/.local/bin/thunderbird b/shells/.local/bin/thunderbird
new file mode 100755
index 00000000..47f4f43d
--- /dev/null
+++ b/shells/.local/bin/thunderbird
@@ -0,0 +1,5 @@
+#!/bin/sh
+_command=$(command-shadowed -v "${0}")
+private_directory="${XDG_CONFIG_HOME:-${HOME}/.config}/mozilla"
+[ -d "${private_directory}" ] || mkdir -p "${private_directory}"
+firejail --private="${private_directory}" "${_command}" "${@}"
diff --git a/shells/.local/bin/awk-lint b/utils/.local/bin/awk-lint
similarity index 94%
rename from shells/.local/bin/awk-lint
rename to utils/.local/bin/awk-lint
index 914a5fbf..510d25a4 100755
--- a/shells/.local/bin/awk-lint
+++ b/utils/.local/bin/awk-lint
@@ -1,5 +1,5 @@
 #!/bin/sh
-set -eau
+set -aeu
 file=${1}
 echo '
     BEGIN {