diff --git a/README.md b/README.md
index 31dd425..a709204 100644
--- a/README.md
+++ b/README.md
@@ -29,7 +29,7 @@ http_archive(
     name = "bazel-zig-cc",
     sha256 = "cd2629843fe4ba20cf29e1d73cc02559afba640f884e519b6a194a35627cbbf3",
     strip_prefix = "bazel-zig-cc-{}".format(BAZEL_ZIG_CC_VERSION),
-    urls = ["https://git.sr.ht/~motiejus/bazel-zig-cc/archive/{}.tar.gz".format(BAZEL_ZIG_CC_VERSION)],
+    urls = ["https://git.sr.ht/~motiejus/bazel-zig-cc/archive/{}.{_ext}".format(BAZEL_ZIG_CC_VERSION)],
 )
 
 load("@bazel-zig-cc//toolchain:defs.bzl", zig_toolchains = "toolchains")
@@ -40,7 +40,7 @@ load("@bazel-zig-cc//toolchain:defs.bzl", zig_toolchains = "toolchains")
 zig_toolchains(
     version = "<...>",
     url_formats = [
-        "https://example.org/zig/zig-{host_platform}-{version}.tar.xz",
+        "https://example.org/zig/zig-{host_platform}-{version}.{_ext}",
     ],
     host_platform_sha256 = { ... },
 )
@@ -320,11 +320,10 @@ is currently not implemented.
 target macos.10 (Catalina), macos.11 (Big Sur) or macos.12 (Monterey). It
 currently targets the lowest version, without ability to change it.
 
-## Windows: output file extensions
+## Windows only: output file extensions
 
-Bazel won't use common Windows file extensions for built output binaries.
-Instead, it will generate binaries with common Unix extensions that you might
-have to manually rename before deploying them to an actual Windows system:
+For Windows targets Bazel uses Unix extensions for output binaries. Those may
+need to be renamed before deploying to the Windows system. Here is a primer:
 
 | Binary type    | Bazel extension | Windows extension |
 |----------------|-----------------|-------------------|
diff --git a/relnotes.awk b/relnotes.awk
index 3ac8a2f..a24720a 100755
--- a/relnotes.awk
+++ b/relnotes.awk
@@ -14,7 +14,7 @@ BEGIN {stage=0};
     print "    name = \"bazel-zig-cc\","
     print "    sha256 = \""sha256sum"\","
     print "    strip_prefix = \"bazel-zig-cc-{}\".format(BAZEL_ZIG_CC_VERSION),"
-    print "    urls = [\"https://git.sr.ht/~motiejus/bazel-zig-cc/archive/{}.tar.gz\".format(BAZEL_ZIG_CC_VERSION)],"
+    print "    urls = [\"https://git.sr.ht/~motiejus/bazel-zig-cc/archive/{}.{_ext}\".format(BAZEL_ZIG_CC_VERSION)],"
     print ")"
     stage=1
     next
diff --git a/toolchain/defs.bzl b/toolchain/defs.bzl
index df2441d..e165a86 100644
--- a/toolchain/defs.bzl
+++ b/toolchain/defs.bzl
@@ -16,21 +16,21 @@ __asm__(".symver fcntl64, fcntl@GLIBC_2.2.5");
 """
 
 # Official recommended version. Should use this when we have a usable release.
-URL_FORMAT_RELEASE = "https://ziglang.org/download/{version}/zig-{host_platform}-{version}.{ext}"
+URL_FORMAT_RELEASE = "https://ziglang.org/download/{version}/zig-{host_platform}-{version}.{_ext}"
 
 # Caution: nightly releases are purged from ziglang.org after ~90 days. A real
 # solution would be to allow the downstream project specify their own mirrors.
 # This is explained in
 # https://sr.ht/~motiejus/bazel-zig-cc/#alternative-download-urls and is
 # awaiting my attention or your contribution.
-URL_FORMAT_NIGHTLY = "https://ziglang.org/builds/zig-{host_platform}-{version}.{ext}"
+URL_FORMAT_NIGHTLY = "https://ziglang.org/builds/zig-{host_platform}-{version}.{_ext}"
 
 # Author's mirror that doesn't purge the nightlies so aggressively. I will be
 # cleaning those up manually only after the artifacts are not in use for many
 # months in bazel-zig-cc. dl.jakstys.lt is a small x86_64 server with an NVMe
 # drive sitting in my home closet on a 1GB/s symmetric residential connection,
 # which, as of writing, has been quite reliable.
-URL_FORMAT_JAKSTYS = "https://dl.jakstys.lt/zig/zig-{host_platform}-{version}.{ext}"
+URL_FORMAT_JAKSTYS = "https://dl.jakstys.lt/zig/zig-{host_platform}-{version}.{_ext}"
 
 _VERSION = "0.10.0-dev.2252+a4369918b"
 
@@ -128,7 +128,7 @@ def _zig_repository_impl(repository_ctx):
     zig_sha256 = repository_ctx.attr.host_platform_sha256[host_platform]
     zig_ext = repository_ctx.attr.host_platform_ext[host_platform]
     format_vars = {
-        "ext": zig_ext,
+        "_ext": zig_ext,
         "version": repository_ctx.attr.version,
         "host_platform": host_platform,
     }