diff --git a/Library/Homebrew/brew.sh b/Library/Homebrew/brew.sh
index 48f900801e..483079a8f0 100644
--- a/Library/Homebrew/brew.sh
+++ b/Library/Homebrew/brew.sh
@@ -24,6 +24,25 @@ else
   HOMEBREW_CELLAR="${HOMEBREW_PREFIX}/Cellar"
 fi
 
+HOMEBREW_MACOS_ARM_DEFAULT_PREFIX="/opt/homebrew"
+HOMEBREW_MACOS_ARM_DEFAULT_REPOSITORY="${HOMEBREW_MACOS_ARM_DEFAULT_PREFIX}"
+HOMEBREW_LINUX_DEFAULT_PREFIX="/home/linuxbrew/.linuxbrew"
+HOMEBREW_LINUX_DEFAULT_REPOSITORY="${HOMEBREW_LINUX_DEFAULT_PREFIX}/Homebrew"
+HOMEBREW_GENERIC_DEFAULT_PREFIX="/usr/local"
+HOMEBREW_GENERIC_DEFAULT_REPOSITORY="${HOMEBREW_GENERIC_DEFAULT_PREFIX}/Homebrew"
+if [[ -n "${HOMEBREW_MACOS}" && "${HOMEBREW_PROCESSOR}" == "arm64" ]]
+then
+  HOMEBREW_DEFAULT_PREFIX="${HOMEBREW_MACOS_ARM_DEFAULT_PREFIX}"
+  HOMEBREW_DEFAULT_REPOSITORY="${HOMEBREW_MACOS_ARM_DEFAULT_REPOSITORY}"
+elif [[ -n "${HOMEBREW_LINUX}" ]]
+then
+  HOMEBREW_DEFAULT_PREFIX="${HOMEBREW_LINUX_DEFAULT_PREFIX}"
+  HOMEBREW_DEFAULT_REPOSITORY="${HOMEBREW_LINUX_DEFAULT_REPOSITORY}"
+else
+  HOMEBREW_DEFAULT_PREFIX="${HOMEBREW_GENERIC_DEFAULT_PREFIX}"
+  HOMEBREW_DEFAULT_REPOSITORY="${HOMEBREW_GENERIC_DEFAULT_REPOSITORY}"
+fi
+
 if [[ -n "${HOMEBREW_MACOS}" ]]
 then
   HOMEBREW_DEFAULT_CACHE="${HOME}/Library/Caches/Homebrew"
@@ -448,6 +467,17 @@ case "$*" in
     ;;
 esac
 
+# TODO: bump version when new macOS is released or announced
+# and also update references in docs/Installation.md,
+# https://github.com/Homebrew/install/blob/HEAD/install.sh and
+# MacOSVersions::SYMBOLS
+HOMEBREW_MACOS_NEWEST_UNSUPPORTED="14"
+# TODO: bump version when new macOS is released and also update
+# references in docs/Installation.md and
+# https://github.com/Homebrew/install/blob/HEAD/install.sh
+HOMEBREW_MACOS_OLDEST_SUPPORTED="11"
+HOMEBREW_MACOS_OLDEST_ALLOWED="10.11"
+
 if [[ -n "${HOMEBREW_MACOS}" ]]
 then
   HOMEBREW_PRODUCT="Homebrew"
@@ -467,6 +497,10 @@ then
   # Intentionally set this variable by exploding another.
   # shellcheck disable=SC2086,SC2183
   printf -v HOMEBREW_MACOS_VERSION_NUMERIC "%02d%02d%02d" ${HOMEBREW_MACOS_VERSION//./ }
+  # shellcheck disable=SC2248
+  printf -v HOMEBREW_MACOS_OLDEST_SUPPORTED_NUMERIC "%02d%02d%02d" ${HOMEBREW_MACOS_OLDEST_SUPPORTED//./ }
+  # shellcheck disable=SC2248
+  printf -v HOMEBREW_MACOS_OLDEST_ALLOWED_NUMERIC "%02d%02d%02d" ${HOMEBREW_MACOS_OLDEST_ALLOWED//./ }
 
   # Don't include minor versions for Big Sur and later.
   if [[ "${HOMEBREW_MACOS_VERSION_NUMERIC}" -gt "110000" ]]
@@ -477,7 +511,7 @@ then
   fi
 
   # Refuse to run on pre-El Capitan
-  if [[ "${HOMEBREW_MACOS_VERSION_NUMERIC}" -lt "101100" ]]
+  if [[ "${HOMEBREW_MACOS_VERSION_NUMERIC}" -lt "${HOMEBREW_MACOS_OLDEST_ALLOWED_NUMERIC}" ]]
   then
     printf "ERROR: Your version of macOS (%s) is too old to run Homebrew!\\n" "${HOMEBREW_MACOS_VERSION}" >&2
     if [[ "${HOMEBREW_MACOS_VERSION_NUMERIC}" -lt "100700" ]]
@@ -524,6 +558,12 @@ then
     # shellcheck disable=SC2034
     HOMEBREW_MACOS_SYSTEM_RUBY_NEW_ENOUGH="1"
   fi
+
+  # Don't support API at this time for older macOS versions.
+  if [[ "${HOMEBREW_MACOS_VERSION_NUMERIC}" -lt "${HOMEBREW_MACOS_OLDEST_SUPPORTED_NUMERIC}" ]]
+  then
+    export HOMEBREW_NO_INSTALL_FROM_API=1
+  fi
 else
   HOMEBREW_PRODUCT="${HOMEBREW_SYSTEM}brew"
   [[ -n "${HOMEBREW_LINUX}" ]] && HOMEBREW_OS_VERSION="$(lsb_release -s -d 2>/dev/null)"
@@ -596,6 +636,12 @@ Your Git executable: $(unset git && type -p "${HOMEBREW_GIT}")"
   fi
 fi
 
+# Generic OS or non-default prefix: API not supported.
+if [[ (-z "${HOMEBREW_MACOS}" && -z "${HOMEBREW_LINUX}") || "${HOMEBREW_PREFIX}" != "${HOMEBREW_DEFAULT_PREFIX}" ]]
+then
+  export HOMEBREW_NO_INSTALL_FROM_API=1
+fi
+
 setup_ca_certificates() {
   if [[ -n "${HOMEBREW_FORCE_BREWED_CA_CERTIFICATES}" && -f "${HOMEBREW_PREFIX}/etc/ca-certificates/cert.pem" ]]
   then
@@ -638,6 +684,14 @@ HOMEBREW_CURL_SPEED_LIMIT=100
 HOMEBREW_CURL_SPEED_TIME=5
 
 export HOMEBREW_VERSION
+export HOMEBREW_MACOS_ARM_DEFAULT_PREFIX
+export HOMEBREW_LINUX_DEFAULT_PREFIX
+export HOMEBREW_GENERIC_DEFAULT_PREFIX
+export HOMEBREW_DEFAULT_PREFIX
+export HOMEBREW_MACOS_ARM_DEFAULT_REPOSITORY
+export HOMEBREW_LINUX_DEFAULT_REPOSITORY
+export HOMEBREW_GENERIC_DEFAULT_REPOSITORY
+export HOMEBREW_DEFAULT_REPOSITORY
 export HOMEBREW_DEFAULT_CACHE
 export HOMEBREW_CACHE
 export HOMEBREW_DEFAULT_LOGS
@@ -661,6 +715,9 @@ export HOMEBREW_PRODUCT
 export HOMEBREW_OS_VERSION
 export HOMEBREW_MACOS_VERSION
 export HOMEBREW_MACOS_VERSION_NUMERIC
+export HOMEBREW_MACOS_NEWEST_UNSUPPORTED
+export HOMEBREW_MACOS_OLDEST_SUPPORTED
+export HOMEBREW_MACOS_OLDEST_ALLOWED
 export HOMEBREW_USER_AGENT
 export HOMEBREW_USER_AGENT_CURL
 export HOMEBREW_API_DEFAULT_DOMAIN
diff --git a/Library/Homebrew/cask/audit.rb b/Library/Homebrew/cask/audit.rb
index 84fbb6b445..d73531c381 100644
--- a/Library/Homebrew/cask/audit.rb
+++ b/Library/Homebrew/cask/audit.rb
@@ -597,7 +597,7 @@ module Cask
         return
       end
 
-      return if min_os_string <= MacOS::Version::OLDEST_ALLOWED
+      return if min_os_string <= HOMEBREW_MACOS_OLDEST_ALLOWED
 
       cask_min_os = cask.depends_on.macos&.version
 
diff --git a/Library/Homebrew/cask/cask.rb b/Library/Homebrew/cask/cask.rb
index cc97dba205..6810544d82 100644
--- a/Library/Homebrew/cask/cask.rb
+++ b/Library/Homebrew/cask/cask.rb
@@ -272,7 +272,7 @@ module Cask
     alias == eql?
 
     def to_h
-      if loaded_from_api && Homebrew::EnvConfig.install_from_api?
+      if loaded_from_api && !Homebrew::EnvConfig.no_install_from_api?
         json_cask = Homebrew::API::Cask.all_casks[token]
         return api_to_local_hash(Homebrew::API.merge_variations(json_cask))
       end
@@ -313,7 +313,7 @@ module Cask
     end
 
     def to_hash_with_variations
-      if loaded_from_api && Homebrew::EnvConfig.install_from_api?
+      if loaded_from_api && !Homebrew::EnvConfig.no_install_from_api?
         return api_to_local_hash(Homebrew::API::Cask.all_casks[token])
       end
 
diff --git a/Library/Homebrew/cask/cask_loader.rb b/Library/Homebrew/cask/cask_loader.rb
index 56c80080bd..0473882f5f 100644
--- a/Library/Homebrew/cask/cask_loader.rb
+++ b/Library/Homebrew/cask/cask_loader.rb
@@ -215,7 +215,7 @@ module Cask
       FLIGHT_STANZAS = [:preflight, :postflight, :uninstall_preflight, :uninstall_postflight].freeze
 
       def self.can_load?(ref)
-        return false unless Homebrew::EnvConfig.install_from_api?
+        return false if Homebrew::EnvConfig.no_install_from_api?
         return false unless ref.is_a?(String)
         return false unless ref.match?(HOMEBREW_MAIN_TAP_CASK_REGEX)
 
diff --git a/Library/Homebrew/cmd/install.rb b/Library/Homebrew/cmd/install.rb
index bfde37fc5c..886631f820 100644
--- a/Library/Homebrew/cmd/install.rb
+++ b/Library/Homebrew/cmd/install.rb
@@ -158,7 +158,7 @@ module Homebrew
       next unless name =~ HOMEBREW_TAP_FORMULA_REGEX
 
       tap = Tap.fetch(Regexp.last_match(1), Regexp.last_match(2))
-      next if (tap.core_tap? || tap == "homebrew/cask") && EnvConfig.install_from_api?
+      next if (tap.core_tap? || tap == "homebrew/cask") && !EnvConfig.no_install_from_api?
 
       tap.install unless tap.installed?
     end
diff --git a/Library/Homebrew/cmd/untap.rb b/Library/Homebrew/cmd/untap.rb
index 5245f4ad78..89b8421536 100644
--- a/Library/Homebrew/cmd/untap.rb
+++ b/Library/Homebrew/cmd/untap.rb
@@ -25,9 +25,9 @@ module Homebrew
     args = untap_args.parse
 
     args.named.to_installed_taps.each do |tap|
-      odie "Untapping #{tap} is not allowed" if tap.core_tap? && !Homebrew::EnvConfig.install_from_api?
+      odie "Untapping #{tap} is not allowed" if tap.core_tap? && Homebrew::EnvConfig.no_install_from_api?
 
-      if !Homebrew::EnvConfig.install_from_api? || (!tap.core_tap? && tap != "homebrew/cask")
+      if Homebrew::EnvConfig.no_install_from_api? || (!tap.core_tap? && tap != "homebrew/cask")
         installed_tap_formulae = Formula.installed.select { |formula| formula.tap == tap }
         installed_tap_casks = Cask::Caskroom.casks.select { |cask| cask.tap == tap }
 
diff --git a/Library/Homebrew/cmd/update-report.rb b/Library/Homebrew/cmd/update-report.rb
index 7d1ec072f2..69b2efeb5d 100644
--- a/Library/Homebrew/cmd/update-report.rb
+++ b/Library/Homebrew/cmd/update-report.rb
@@ -146,7 +146,7 @@ module Homebrew
     end
 
     # Check if we can parse the JSON and do any Ruby-side follow-up.
-    if Homebrew::EnvConfig.install_from_api?
+    unless Homebrew::EnvConfig.no_install_from_api?
       Homebrew::API::Formula.write_names_and_aliases
       Homebrew::API::Cask.write_names
     end
@@ -161,7 +161,7 @@ module Homebrew
     updated_taps = []
     Tap.each do |tap|
       next unless tap.git?
-      next if (tap.core_tap? || tap == "homebrew/cask") && Homebrew::EnvConfig.install_from_api?
+      next if (tap.core_tap? || tap == "homebrew/cask") && !Homebrew::EnvConfig.no_install_from_api?
 
       if ENV["HOMEBREW_MIGRATE_LINUXBREW_FORMULAE"].present? && tap.core_tap? &&
          Settings.read("linuxbrewmigrated") != "true"
@@ -275,7 +275,7 @@ module Homebrew
 
   def install_core_tap_if_necessary
     return if ENV["HOMEBREW_UPDATE_TEST"]
-    return if Homebrew::EnvConfig.install_from_api?
+    return unless Homebrew::EnvConfig.no_install_from_api?
     return if Homebrew::EnvConfig.automatically_set_no_install_from_api?
 
     core_tap = CoreTap.instance
diff --git a/Library/Homebrew/default_prefix.rb b/Library/Homebrew/default_prefix.rb
index 81c85ebcaa..6aaf1351a5 100644
--- a/Library/Homebrew/default_prefix.rb
+++ b/Library/Homebrew/default_prefix.rb
@@ -2,8 +2,6 @@
 # frozen_string_literal: true
 
 module Homebrew
-  DEFAULT_PREFIX = HOMEBREW_DEFAULT_PREFIX
-  DEFAULT_REPOSITORY = HOMEBREW_DEFAULT_REPOSITORY
+  DEFAULT_PREFIX = ENV.fetch("HOMEBREW_DEFAULT_PREFIX").freeze
+  DEFAULT_REPOSITORY = ENV.fetch("HOMEBREW_DEFAULT_REPOSITORY").freeze
 end
-
-require "extend/os/default_prefix"
diff --git a/Library/Homebrew/dev-cmd/audit.rb b/Library/Homebrew/dev-cmd/audit.rb
index 6e5c27d7f3..ff0ebb3de8 100644
--- a/Library/Homebrew/dev-cmd/audit.rb
+++ b/Library/Homebrew/dev-cmd/audit.rb
@@ -327,7 +327,7 @@ module Homebrew
   end
 
   def without_api(&block)
-    return yield unless Homebrew::EnvConfig.install_from_api?
+    return yield if Homebrew::EnvConfig.no_install_from_api?
 
     with_env(HOMEBREW_NO_INSTALL_FROM_API: "1", HOMEBREW_AUTOMATICALLY_SET_NO_INSTALL_FROM_API: "1", &block)
   end
diff --git a/Library/Homebrew/diagnostic.rb b/Library/Homebrew/diagnostic.rb
index ff8508a188..6b57247b20 100644
--- a/Library/Homebrew/diagnostic.rb
+++ b/Library/Homebrew/diagnostic.rb
@@ -522,7 +522,7 @@ module Homebrew
       def check_coretap_integrity
         coretap = CoreTap.instance
         unless coretap.installed?
-          return if EnvConfig.install_from_api?
+          return unless EnvConfig.no_install_from_api?
 
           CoreTap.ensure_installed!
         end
@@ -821,7 +821,7 @@ module Homebrew
         deleted_formulae = kegs.map do |keg|
           next if Formulary.tap_paths(keg.name).any?
 
-          if !CoreTap.instance.installed? && EnvConfig.install_from_api?
+          if !CoreTap.instance.installed? && !EnvConfig.no_install_from_api?
             # Formulae installed with HOMEBREW_INSTALL_FROM_API should not count as deleted formulae
             # but may not have a tap listed in their tab
             tap = Tab.for_keg(keg).tap
diff --git a/Library/Homebrew/env_config.rb b/Library/Homebrew/env_config.rb
index 1d2431cb0c..6301e54483 100644
--- a/Library/Homebrew/env_config.rb
+++ b/Library/Homebrew/env_config.rb
@@ -499,13 +499,5 @@ module Homebrew
     def automatically_set_no_install_from_api?
       ENV["HOMEBREW_AUTOMATICALLY_SET_NO_INSTALL_FROM_API"].present?
     end
-
-    sig { returns(T::Boolean) }
-    def install_from_api?
-      return false if OS.unsupported_configuration?
-      return false unless Homebrew.default_prefix?
-
-      ENV["HOMEBREW_NO_INSTALL_FROM_API"].blank?
-    end
   end
 end
diff --git a/Library/Homebrew/extend/os/default_prefix.rb b/Library/Homebrew/extend/os/default_prefix.rb
deleted file mode 100644
index 01051c964c..0000000000
--- a/Library/Homebrew/extend/os/default_prefix.rb
+++ /dev/null
@@ -1,8 +0,0 @@
-# typed: true
-# frozen_string_literal: true
-
-if OS.mac?
-  require "extend/os/mac/default_prefix"
-elsif OS.linux?
-  require "extend/os/linux/default_prefix"
-end
diff --git a/Library/Homebrew/extend/os/linux/default_prefix.rb b/Library/Homebrew/extend/os/linux/default_prefix.rb
deleted file mode 100644
index d72987236a..0000000000
--- a/Library/Homebrew/extend/os/linux/default_prefix.rb
+++ /dev/null
@@ -1,10 +0,0 @@
-# typed: true
-# frozen_string_literal: true
-
-module Homebrew
-  remove_const(:DEFAULT_PREFIX)
-  DEFAULT_PREFIX = HOMEBREW_LINUX_DEFAULT_PREFIX
-
-  remove_const(:DEFAULT_REPOSITORY)
-  DEFAULT_REPOSITORY = HOMEBREW_LINUX_DEFAULT_REPOSITORY
-end
diff --git a/Library/Homebrew/extend/os/linux/diagnostic.rb b/Library/Homebrew/extend/os/linux/diagnostic.rb
index 110651a209..a4d69332d2 100644
--- a/Library/Homebrew/extend/os/linux/diagnostic.rb
+++ b/Library/Homebrew/extend/os/linux/diagnostic.rb
@@ -121,7 +121,7 @@ module Homebrew
       end
 
       def check_linuxbrew_core
-        return if Homebrew::EnvConfig.install_from_api?
+        return unless Homebrew::EnvConfig.no_install_from_api?
         return unless CoreTap.instance.linuxbrew_core?
 
         <<~EOS
diff --git a/Library/Homebrew/extend/os/mac/default_prefix.rb b/Library/Homebrew/extend/os/mac/default_prefix.rb
deleted file mode 100644
index 330e326598..0000000000
--- a/Library/Homebrew/extend/os/mac/default_prefix.rb
+++ /dev/null
@@ -1,17 +0,0 @@
-# typed: true
-# frozen_string_literal: true
-
-require "simulate_system"
-
-module Homebrew
-  if Hardware::CPU.arm? || Homebrew::SimulateSystem.simulating_or_running_on_linux?
-    remove_const(:DEFAULT_PREFIX)
-    remove_const(:DEFAULT_REPOSITORY)
-
-    DEFAULT_PREFIX, DEFAULT_REPOSITORY = if Hardware::CPU.arm?
-      [HOMEBREW_MACOS_ARM_DEFAULT_PREFIX, HOMEBREW_MACOS_ARM_DEFAULT_REPOSITORY]
-    elsif Homebrew::SimulateSystem.simulating_or_running_on_linux?
-      [HOMEBREW_LINUX_DEFAULT_PREFIX, HOMEBREW_LINUX_DEFAULT_REPOSITORY]
-    end
-  end
-end
diff --git a/Library/Homebrew/extend/os/mac/tap.rb b/Library/Homebrew/extend/os/mac/tap.rb
index a2f8314a2a..97abb1a3fe 100644
--- a/Library/Homebrew/extend/os/mac/tap.rb
+++ b/Library/Homebrew/extend/os/mac/tap.rb
@@ -4,7 +4,7 @@
 class Tap
   def self.install_default_cask_tap_if_necessary(force: false)
     return false if default_cask_tap.installed?
-    return false if Homebrew::EnvConfig.install_from_api?
+    return false unless Homebrew::EnvConfig.no_install_from_api?
     return false if Homebrew::EnvConfig.automatically_set_no_install_from_api?
     return false if !force && Tap.untapped_official_taps.include?(default_cask_tap.name)
 
diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 0986d75213..869e49b409 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -2202,7 +2202,7 @@ class Formula
     hash = to_hash
 
     # Take from API, merging in local install status.
-    if self.class.loaded_from_api && Homebrew::EnvConfig.install_from_api?
+    if self.class.loaded_from_api && !Homebrew::EnvConfig.no_install_from_api?
       json_formula = Homebrew::API::Formula.all_formulae[name].dup
       json_formula["name"] = hash["name"]
       json_formula["installed"] = hash["installed"]
diff --git a/Library/Homebrew/formulary.rb b/Library/Homebrew/formulary.rb
index ee45ee0faa..6d1b16708e 100644
--- a/Library/Homebrew/formulary.rb
+++ b/Library/Homebrew/formulary.rb
@@ -748,7 +748,7 @@ module Formulary
     when URL_START_REGEX
       return FromUrlLoader.new(ref, from: from)
     when HOMEBREW_TAP_FORMULA_REGEX
-      if ref.start_with?("homebrew/core/") && Homebrew::EnvConfig.install_from_api?
+      if ref.start_with?("homebrew/core/") && !Homebrew::EnvConfig.no_install_from_api?
         name = ref.split("/", 3).last
         return FormulaAPILoader.new(name) if Homebrew::API::Formula.all_formulae.key?(name)
         return AliasAPILoader.new(name) if Homebrew::API::Formula.all_aliases.key?(name)
@@ -760,7 +760,7 @@ module Formulary
     pathname_ref = Pathname.new(ref)
     return FromPathLoader.new(ref) if File.extname(ref) == ".rb" && pathname_ref.expand_path.exist?
 
-    if Homebrew::EnvConfig.install_from_api?
+    unless Homebrew::EnvConfig.no_install_from_api?
       return FormulaAPILoader.new(ref) if Homebrew::API::Formula.all_formulae.key?(ref)
       return AliasAPILoader.new(ref) if Homebrew::API::Formula.all_aliases.key?(ref)
     end
diff --git a/Library/Homebrew/global.rb b/Library/Homebrew/global.rb
index 0f8362cbcd..c773b8bb0f 100644
--- a/Library/Homebrew/global.rb
+++ b/Library/Homebrew/global.rb
@@ -59,14 +59,18 @@ HOMEBREW_USER_AGENT_FAKE_SAFARI =
   "(KHTML, like Gecko) Version/10.0.3 Safari/602.4.8"
 HOMEBREW_GITHUB_PACKAGES_AUTH = ENV.fetch("HOMEBREW_GITHUB_PACKAGES_AUTH").freeze
 
-HOMEBREW_DEFAULT_PREFIX = "/usr/local"
-HOMEBREW_DEFAULT_REPOSITORY = "#{HOMEBREW_DEFAULT_PREFIX}/Homebrew"
-HOMEBREW_MACOS_ARM_DEFAULT_PREFIX = "/opt/homebrew"
-HOMEBREW_MACOS_ARM_DEFAULT_REPOSITORY = HOMEBREW_MACOS_ARM_DEFAULT_PREFIX
-HOMEBREW_LINUX_DEFAULT_PREFIX = "/home/linuxbrew/.linuxbrew"
-HOMEBREW_LINUX_DEFAULT_REPOSITORY = "#{HOMEBREW_LINUX_DEFAULT_PREFIX}/Homebrew"
+HOMEBREW_DEFAULT_PREFIX = ENV.fetch("HOMEBREW_GENERIC_DEFAULT_PREFIX").freeze
+HOMEBREW_DEFAULT_REPOSITORY = ENV.fetch("HOMEBREW_GENERIC_DEFAULT_REPOSITORY").freeze
+HOMEBREW_MACOS_ARM_DEFAULT_PREFIX = ENV.fetch("HOMEBREW_MACOS_ARM_DEFAULT_PREFIX").freeze
+HOMEBREW_MACOS_ARM_DEFAULT_REPOSITORY = ENV.fetch("HOMEBREW_MACOS_ARM_DEFAULT_REPOSITORY").freeze
+HOMEBREW_LINUX_DEFAULT_PREFIX = ENV.fetch("HOMEBREW_LINUX_DEFAULT_PREFIX").freeze
+HOMEBREW_LINUX_DEFAULT_REPOSITORY = ENV.fetch("HOMEBREW_LINUX_DEFAULT_REPOSITORY").freeze
 HOMEBREW_PREFIX_PLACEHOLDER = "$HOMEBREW_PREFIX"
 
+HOMEBREW_MACOS_NEWEST_UNSUPPORTED = ENV.fetch("HOMEBREW_MACOS_NEWEST_UNSUPPORTED").freeze
+HOMEBREW_MACOS_OLDEST_SUPPORTED = ENV.fetch("HOMEBREW_MACOS_OLDEST_SUPPORTED").freeze
+HOMEBREW_MACOS_OLDEST_ALLOWED = ENV.fetch("HOMEBREW_MACOS_OLDEST_ALLOWED").freeze
+
 HOMEBREW_PULL_API_REGEX =
   %r{https://api\.github\.com/repos/([\w-]+)/([\w-]+)?/pulls/(\d+)}.freeze
 HOMEBREW_PULL_OR_COMMIT_URL_REGEX =
diff --git a/Library/Homebrew/os/mac/version.rb b/Library/Homebrew/os/mac/version.rb
index 79ddbec4b2..fd709f72f2 100644
--- a/Library/Homebrew/os/mac/version.rb
+++ b/Library/Homebrew/os/mac/version.rb
@@ -13,21 +13,6 @@ module OS
     class Version < ::Version
       extend T::Sig
 
-      # TODO: bump version when new macOS is released or announced
-      # and also update references in docs/Installation.md,
-      # https://github.com/Homebrew/install/blob/HEAD/install.sh and
-      # MacOSVersions::SYMBOLS
-      NEWEST_UNSUPPORTED = "14"
-      private_constant :NEWEST_UNSUPPORTED
-
-      # TODO: bump version when new macOS is released and also update
-      # references in docs/Installation.md and
-      # https://github.com/Homebrew/install/blob/HEAD/install.sh
-      OLDEST_SUPPORTED = "11"
-      private_constant :OLDEST_SUPPORTED
-
-      OLDEST_ALLOWED = "10.11"
-
       sig { params(version: Symbol).returns(T.attached_class) }
       def self.from_symbol(version)
         str = MacOSVersions::SYMBOLS.fetch(version) { raise MacOSVersionError, version }
@@ -79,12 +64,12 @@ module OS
 
       sig { returns(T::Boolean) }
       def outdated_release?
-        self < OLDEST_SUPPORTED
+        self < HOMEBREW_MACOS_OLDEST_SUPPORTED
       end
 
       sig { returns(T::Boolean) }
       def prerelease?
-        self >= NEWEST_UNSUPPORTED
+        self >= HOMEBREW_MACOS_NEWEST_UNSUPPORTED
       end
 
       # For {OS::Mac::Version} compatibility.
diff --git a/Library/Homebrew/requirements/macos_requirement.rb b/Library/Homebrew/requirements/macos_requirement.rb
index 5bc13680ce..0cff48ac90 100644
--- a/Library/Homebrew/requirements/macos_requirement.rb
+++ b/Library/Homebrew/requirements/macos_requirement.rb
@@ -43,7 +43,7 @@ class MacOSRequirement < Requirement
       end
 
       # Otherwise fallback to the oldest allowed if comparator is >=.
-      MacOS::Version.new(MacOS::Version::OLDEST_ALLOWED) if comparator == ">="
+      MacOS::Version.new(HOMEBREW_MACOS_OLDEST_ALLOWED) if comparator == ">="
     end
 
     @comparator = comparator
diff --git a/Library/Homebrew/search.rb b/Library/Homebrew/search.rb
index 2644affa88..5544f24845 100644
--- a/Library/Homebrew/search.rb
+++ b/Library/Homebrew/search.rb
@@ -137,7 +137,7 @@ module Homebrew
         c.sub(%r{^homebrew/cask.*/}, "")
       end
 
-      if !Tap.fetch("homebrew/cask").installed? && Homebrew::EnvConfig.install_from_api?
+      if !Tap.fetch("homebrew/cask").installed? && !Homebrew::EnvConfig.no_install_from_api?
         cask_tokens += Homebrew::API::Cask.all_casks.keys
       end
 
diff --git a/Library/Homebrew/tap.rb b/Library/Homebrew/tap.rb
index 8024e2e112..f165ffcc4a 100644
--- a/Library/Homebrew/tap.rb
+++ b/Library/Homebrew/tap.rb
@@ -723,7 +723,7 @@ class Tap
   # @private
   sig { returns(T::Boolean) }
   def should_report_analytics?
-    return Homebrew::EnvConfig.install_from_api? && official? unless installed?
+    return !Homebrew::EnvConfig.no_install_from_api? && official? unless installed?
 
     !private?
   end
@@ -859,7 +859,7 @@ class CoreTap < Tap
   sig { void }
   def self.ensure_installed!
     return if instance.installed?
-    return if Homebrew::EnvConfig.install_from_api?
+    return unless Homebrew::EnvConfig.no_install_from_api?
     return if Homebrew::EnvConfig.automatically_set_no_install_from_api?
 
     # Tests override homebrew-core locations and we don't want to auto-tap in them.
@@ -870,7 +870,7 @@ class CoreTap < Tap
 
   sig { returns(String) }
   def remote
-    super if installed? || !Homebrew::EnvConfig.install_from_api?
+    super if installed? || Homebrew::EnvConfig.no_install_from_api?
 
     Homebrew::EnvConfig.core_git_remote
   end
@@ -893,7 +893,7 @@ class CoreTap < Tap
   # @private
   sig { params(manual: T::Boolean).void }
   def uninstall(manual: false)
-    raise "Tap#uninstall is not available for CoreTap" unless Homebrew::EnvConfig.install_from_api?
+    raise "Tap#uninstall is not available for CoreTap" if Homebrew::EnvConfig.no_install_from_api?
 
     super
   end
@@ -988,7 +988,7 @@ class CoreTap < Tap
   # @private
   sig { returns(T::Array[String]) }
   def aliases
-    return super if installed? || !Homebrew::EnvConfig.install_from_api?
+    return super if installed? || Homebrew::EnvConfig.no_install_from_api?
 
     Homebrew::API::Formula.all_aliases.keys
   end
@@ -996,7 +996,7 @@ class CoreTap < Tap
   # @private
   sig { returns(T::Array[String]) }
   def formula_names
-    return super if installed? || !Homebrew::EnvConfig.install_from_api?
+    return super if installed? || Homebrew::EnvConfig.no_install_from_api?
 
     Homebrew::API::Formula.all_formulae.keys
   end
diff --git a/Library/Homebrew/test/cask/cask_loader/from_api_loader_spec.rb b/Library/Homebrew/test/cask/cask_loader/from_api_loader_spec.rb
index db8a16dcaa..a10e101ae0 100644
--- a/Library/Homebrew/test/cask/cask_loader/from_api_loader_spec.rb
+++ b/Library/Homebrew/test/cask/cask_loader/from_api_loader_spec.rb
@@ -28,8 +28,8 @@ describe Cask::CaskLoader::FromAPILoader, :cask do
     context "when not using the API" do
       before do
         allow(Homebrew::EnvConfig)
-          .to receive(:install_from_api?)
-          .and_return(false)
+          .to receive(:no_install_from_api?)
+          .and_return(true)
       end
 
       it "returns false" do
@@ -40,8 +40,8 @@ describe Cask::CaskLoader::FromAPILoader, :cask do
     context "when using the API" do
       before do
         allow(Homebrew::EnvConfig)
-          .to receive(:install_from_api?)
-          .and_return(true)
+          .to receive(:no_install_from_api?)
+          .and_return(false)
       end
 
       it "returns true for valid token" do