diff --git a/Makefile b/Makefile
index dbbf83bd..949184c3 100644
--- a/Makefile
+++ b/Makefile
@@ -197,18 +197,25 @@ dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION)-docs-md.zip: docs-md
 dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION)-build-epoch.txt:
 	echo $(SOURCE_DATE_EPOCH) > dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION)-build-epoch.txt
 
-# Build a PEP-503 compatible Simple Repository directory inside of dist/. For details on
-# the layout of that directory and the normalized project name, see: https://peps.python.org/pep-0503/
-# The directory can then be used to install (hashed) artifacts by using `pip` and
-# its `--extra-index-url` argument: https://pip.pypa.io/en/stable/cli/pip_install/#cmdoption-extra-index-url
+# Build a Simple Repository directory inside of dist/. For details on the layout of that directory
+# and the normalized project name, see:
+#
+#  - PEP-503: https://peps.python.org/pep-0503/
+#    Related discussion: https://discuss.python.org/t/what-would-it-look-like-to-deprecate-pep-503/
+#  - PEP 691: https://peps.python.org/pep-0691/
+#
+# The directory can then be used to install (hashed) artifacts by using `pip` and its `--extra-index-url`
+# argument: https://pip.pypa.io/en/stable/cli/pip_install/#cmdoption-extra-index-url
 PROJECT_NAME := $(shell python -c $$'import re; print(re.sub(r"[-_.]+", "-", "$(PACKAGE_NAME)").lower());')
-.PHONY: simple-index
-simple-index: dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION)-py3-none-any.whl dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION).tar.gz
+.PHONY: simple-index-pep503 simple-index-pep691
+simple-index-pep503: dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION)-py3-none-any.whl dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION).tar.gz
 	mkdir -p dist/simple-index/$(PROJECT_NAME)
 	echo -e "<!-- https://peps.python.org/pep-0503/ -->\n<!DOCTYPE html><html lang='en'><head><meta name='pypi:repository-version' content='1.3'><title>Simple Index</title></head><body><a href='/$(PACKAGE_NAME)/'>$(PACKAGE_NAME)</a></body></html>" > dist/simple-index/index.html
 	echo -e "<!-- https://peps.python.org/pep-0503/ -->\n<!DOCTYPE html><html lang='en'><head><meta name='pypi:repository-version' content='1.3'><title>Simple Index: $(PROJECT_NAME)</title></head><body><a href='$(PACKAGE_NAME)-$(PACKAGE_VERSION)-py3-none-any.whl#sha256="$$(python -c "with open('dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION)-py3-none-any.whl', 'rb') as f: import hashlib; print(hashlib.sha256(f.read()).hexdigest());")"'>$(PACKAGE_NAME)-$(PACKAGE_VERSION)-py3-none-any.whl</a><a href='$(PACKAGE_NAME)-$(PACKAGE_VERSION).tar.gz#sha256="$$(python -c "with open('dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION).tar.gz', 'rb') as f: import hashlib; print(hashlib.sha256(f.read()).hexdigest());")"'>$(PACKAGE_NAME)-$(PACKAGE_VERSION).tar.gz</a></body></html>" > dist/simple-index/$(PROJECT_NAME)/index.html
 	cp -f dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION)-py3-none-any.whl dist/simple-index/$(PROJECT_NAME)/
 	cp -f dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION).tar.gz dist/simple-index/$(PROJECT_NAME)/
+simple-index-pep691: dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION)-py3-none-any.whl dist/$(PACKAGE_NAME)-$(PACKAGE_VERSION).tar.gz
+	mkdir -p dist/simple-index/$(PROJECT_NAME)
 
 # Build the HTML and Markdown documentation from the package's source.
 DOCS_SOURCE := $(shell git ls-files docs/source)
