diff --git a/.gitea/workflows/publish-wiki.yml b/.gitea/workflows/publish-wiki.yml
new file mode 100644
index 0000000..87b6546
--- /dev/null
+++ b/.gitea/workflows/publish-wiki.yml
@@ -0,0 +1,38 @@
+# Publish the project's wiki pages to the git host's wiki.
+#
+# On a push to main that changes docs/wiki/, this workflow calls the reusable
+# workflow of TirSystem/github-action, which copies the Markdown pages of
+# docs/wiki/ to the wiki of this repository (framework/process/wiki.md says
+# what the folder holds: English and the PO language as a minimum).
+#
+# INSTALLING THIS FILE IS THE OPT-IN. There is no marker file. A project that
+# does not copy it publishes nothing.
+#
+# Copy it to .gitea/workflows/publish-wiki.yml. Then:
+#   1. Create the secret TOKEN_FOR_GITEA_WIKI in the organization of the
+#      repository: a Gitea token with scope write:repository for a user that
+#      can write this repository (see guides/credentials.md of github-action).
+#   2. Enable the wiki in the repository settings.
+#   3. Keep @v2, or pin the exact release tag together with tools-ref.
+# A runner must be registered for the repository (or its organization).
+#
+# prune: "true" deletes wiki pages that are not in docs/wiki/, so the wiki
+# always equals the folder. Leave it "false" to keep hand-written pages.
+
+name: Publish wiki
+
+on:
+  push:
+    branches: [ main ]
+    paths:
+      - "docs/wiki/**"
+  workflow_dispatch:
+
+jobs:
+  wiki:
+    uses: TirSystem/github-action/.gitea/workflows/publish-wiki-pages.yml@v2
+    with:
+      wiki_dir: docs/wiki
+      prune: "true"
+    secrets:
+      TOKEN_FOR_GITEA_WIKI: ${{ secrets.TOKEN_FOR_GITEA_WIKI }}
diff --git a/README.md b/README.md
index 2ccda12..5b1c4bd 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,50 @@
 # prime-numbers-c
 
+Lists every prime number from 0 to 1,000,000 and reports how long the search
+took. It shows how fast a CPU is, but the result depends on how the program is
+written: algorithm, instruction set (here AVX2), compiler and flags.
+
+Example result on a 13th Gen Intel(R) Core(TM) i5-13600K:
+
+```text
+Found 78498 primes from 0 to 1000000 in 20.977 ms
+```
+
+## Build and run
+
+Needs `gcc` (Linux, or MinGW-w64 / MSYS2 on Windows), `make` and a CPU with AVX2.
+
+```bash
+make
+```
+
+```bash
+make run
+```
+
+```bash
+make clean
+```
+
+The executable is built into `dist/`. The primes go to standard output and the
+timing line to standard error, so this saves the list and still shows the time:
+
+```bash
+./dist/prime_avx2 > primes.txt
+```
+
+## Layout
+
+| Path | Content |
+| --- | --- |
+| `src/prime_avx2.c` | the program |
+| `Makefile` | build rules |
+| `docs/wiki/` | wiki pages, published to the Gitea wiki by `.gitea/workflows/publish-wiki.yml` |
+
+## Documentation
+
+See the wiki: Description, Results and Build and run.
+
+## License
+
+See [LICENSE](LICENSE).