diff --git a/dev-build/muon/Manifest b/dev-build/muon/Manifest
index 57ee3c39d2cc3..b536c53074434 100644
--- a/dev-build/muon/Manifest
+++ b/dev-build/muon/Manifest
@@ -1,3 +1,4 @@
 DIST meson-tests-1e565931348f15f3f9b654f46ab4bf5fa009ca4f.tar.gz 229885 BLAKE2B d53bbc854da00c1a91189f6c4539da782f4ff49d2a57d86c56b9512b8b832f32d094d750055bb0602fe60aff58821e10c5f00663be9479420e29f75fbfba01c9 SHA512 25fdb657a17a33140029600d84cb3182e635749b99af85c432da611349c10576e15d2f79d1f9eaa21e3359b65dd057ef388925c54ebdc9c072e4b24bec3be8f8
 DIST muon-0.2.0.tar.gz 510533 BLAKE2B 6ec67f8875e84fbc2f23f412825dd47b820cd44e97a16d9ac0ab0ba9db6e755a604b66b79d3dbe13d99440daf21c2f0ccbe69661b1fb3c7df3f636c61a0e4dcb SHA512 b2e90048756bdc26bdea24fe227a87ad4d0e57176e217e22ea492a55229c62e2a70243f60af1e162e2dde8468fdda9662a32ea5cfadd69fab95a83499efa077b
 DIST muon-v0.3.0.tar.gz 688544 BLAKE2B 6f5e9f91c1221135d8452b54bd781fb4324586d88503579af243c9889e17330d3d746a0e9fa4480a98d36ec5d55d1c335813bd19da81eaf2ef40dda42d32c418 SHA512 10d8d3d8d5df3898de22ed43fef234766e1884561d797a6462d614fd7be0f22eb7bbf40e096fe44d3e58f72e1fc631ef510f53a1e8ec36d4602ad7d5fe2771b3
+DIST muon-v0.4.0.tar.gz 3435753 BLAKE2B 0eb685ebd22a6314cfa02ab716ae8a1899363d1ce4dc6fd0b42a3fab1ff62358d21abd6c6d2682a78df1fffd2d6cc72abaacfa7eb5174a10d50bdd5dbbf0825c SHA512 2ab817bfe886fff5a9cd00935f19c7c73cc4556aa11a538ca496bdad4cced4dc1608efd05d58b6971640d0543bd7d4486185ed93a26522690cf2e1d348342bb8
diff --git a/dev-build/muon/muon-0.4.0.ebuild b/dev-build/muon/muon-0.4.0.ebuild
new file mode 100644
index 0000000000000..b9d58a6aa3110
--- /dev/null
+++ b/dev-build/muon/muon-0.4.0.ebuild
@@ -0,0 +1,67 @@
+# Copyright 2022-2025 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+inherit edo meson
+
+MESON_TESTS_HASH=1e565931348f15f3f9b654f46ab4bf5fa009ca4f
+MESON_TESTS_DIRNAME="meson-tests-${MESON_TESTS_HASH}"
+
+DESCRIPTION="A meson-compatible build system"
+HOMEPAGE="https://muon.build/"
+SRC_URI="
+	https://muon.build/releases/v${PV}/${PN}-v${PV}.tar.gz
+	test? (
+		 https://git.sr.ht/~lattis/meson-tests/archive/${MESON_TESTS_HASH}.tar.gz
+			-> ${MESON_TESTS_DIRNAME}.tar.gz
+	)
+"
+S="${WORKDIR}/${PN}-v${PV}"
+
+LICENSE="GPL-3"
+SLOT="0"
+KEYWORDS="~amd64 ~arm ~arm64 ~ppc ~ppc64"
+IUSE="+archive +curl +libpkgconf test"
+
+DEPEND="
+	curl? ( net-misc/curl )
+	archive? ( app-arch/libarchive:= )
+	libpkgconf? ( dev-util/pkgconf:= )
+"
+RDEPEND="${DEPEND}"
+BDEPEND="
+	app-text/scdoc
+"
+RESTRICT="!test? ( test )"
+
+src_unpack() {
+	default
+
+	if use test; then
+		edo mv "${WORKDIR}/${MESON_TESTS_DIRNAME}" \
+			"${S}"/tests/project/meson-tests
+	fi
+}
+
+src_prepare() {
+	default
+}
+
+src_configure() {
+	cat >"${T}/program-file.ini" <<-EOF
+	[binaries]
+	git = 'if this exists youre a bad person'
+	EOF
+	local emesonargs=(
+		--native-file="${T}/program-file.ini"
+		$(meson_feature curl libcurl)
+		$(meson_feature archive libarchive)
+		$(meson_feature libpkgconf)
+		-Ddocs=enabled
+		-Dtracy=disabled    # not in repos
+		-Dsamurai=disabled  # patched version of samurai downloaded via wraps
+		-Dreadline=bestline # small vendored dependency
+	)
+	meson_src_configure
+}