Hello, Fediverse!
Introducing Mycorrhiza, a free self-hosted wiki engine, developed by @bouncepaw and the numerous contributors. It features file-based storage, history, a custom markup language, categories, among other features.
Common use-cases: digital gardens, personal websites, diaries, documentation, encyclopediƦ. The project is like 3 years old, so it is probably stable enough.
Take a look: https://mycorrhiza.wiki
It might be available in your OS's repositories.